Double Eagle Build

Get help and share Ideas
kmorin
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Re: Double Eagle Build

#26

Post by kmorin » Thu Sep 11, 2014 9:37 pm

North, please don't ever misunderstand that a semi-retired, somewhat over displacement old boat builder is ever setting the timing here on the Fourm!

Ain't happen'. we're here to help your project and the enjoyment of the Forum's readers as they explore more details about the infinite possibilities of aluminum boat building.

When you need info, please post so we can discuss the next step, decision, idea or design element.

Congratulations, again, Dad! here is my virtual cigar enjoyed by all.... :skipper:

Cheers,
Kevin Morin
Kenai, AK
kmorin

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Re: Double Eagle Build

#27

Post by Northeaster » Mon Sep 29, 2014 2:48 pm

Hi Kevin- Things starting to settle down a bit here . I will take off the mast and haul the sailboat and docks in the next couple of weeks, and pick up about 8 pieces of 1.5" x 3/16" x 20' angle, to use as stringers near the bow, where the bends are greater. I tried tapering the current flat bar stringers (per your posts) but I am still getting the side bending. And, frankly, it seemed so easy to do when I laid on a piece of spare 1.25" angle (while attempting to find the lines, earlier in the build). I feel better going with the angle near the bow. My plan is to leave the flat bar in place for the stern half or so and overlap (backside of angle to side of flat bar) near amidships as I transition from flat bar to angle.
I have too many slots cut anyway in my frames up front, and although they could be filled / repaired - I really like the idea of just cutting a 1.5" swath between the chine and keel, and chine and gunwale, where the angle stringers will be tied down to rest until welded (as in the pic of another boat below). I will only do this where using angle on about 4 stations nearer the bow. Aft, I will leave the flat bar in the single slots I have cut.

I hope to have the stringers in place (but not welded) in about a month, and then start on the hull sheet. Knowing there is a few weeks lead time for 20' sheets, I would like to place my order soon for the hull sheet.
I am leaning towards 3/16" for bottom, topsides and cockpit sole (mainly as costly roll change charges favour the ordering of one thickness, in addition to the merits of easier welding, less distortion, strength, etc. in going with 3/16" vs. the 1/8” called for in the stock 23’ plans.
My bottom sections require two 20' by 4 ft wide sheets and the topsides two 20' require 3' wide sheets. (plus some scraps to get to 25' near the bow). Of course, I will not order 3’ sheets, so it I will order all 4’ sheets and have leftovers.
There will be significant waste / scraps due above extra foot and to the tapering of the sections so I think I will have reasonable leftover for the cockpit sole. If / when short, I can order 8' sheets without additional costs as this is a stock size and I can fill in the sole with those, rather than buy an additional 20' sheet.(let me know if it doesn’t make sense, please)

So, I would appreciate if you could take some time to discuss or recommend a thickness for the new, improved box keel sheet, as if 3/16" is appropriate, it may make sense to order one more 20' sheet, for the keel sides, bottom, and leftovers for cockpit sole. If it requires thicker material, I will just wait on that. I have an “extra” 4’ x 8’ x 3/8” thick sheet which I purchased for the flat keel. I assume the box keel design will allow used of a thinner material??

I don't need all of the drawings and accompanying understanding of the keel design yet (if you are short on time) but for now a thickness recommendation or comment as to my ordering logic or lack thereof would suffice!
Thanks,
Darrell
Attachments
IMG_20131103_093115.jpg

kmorin
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Re: Double Eagle Build

#28

Post by kmorin » Tue Sep 30, 2014 2:13 pm

Northeaster,
I think your idea about the bars being replaced is OK, but the tapers may not have been drastic enough if you're still not getting the bends (in diagonal) as far shapes. However, your idea of switching longs from bars to angles does most of what you'll need; the horizontal or flange of the angle will keep the 'bar' part of the angle nearest the hull fair and without bends in the other plane.

Your idea of trimming the frames to allow the angles my work fine, I'd make sure the flat of the angles' back leg was not welded to the frames FINALLY, until the last minute. The reason is this 1" or 1-1/2" weld will allow the angles to bend in relief of that heat. IF possible I'd want the hull, bottom and topsides tacked to the frame (longs and xverse if planned) fully before I welded those frame to angles to avoid the longs kinking in contraction and relief of bending stresses.

Regarding the scantlings change from 0.125" up to 0.187" that 0.062" addition wt does add strength especially as the framing was intended to support the thinner material. The welding will be somewhat simplified, depending on your welding skills at the time you weld out, and the resulting boat will be very heavily built, not a bad thing.

I'd consider using 0.160" (5/32") for the topsides, if your supplier can order it? I use 160 for decks as well, 125 can require more closely spaced framing in decks but 160 comes close to 187 in the same application. Again, I'm not sure about your supplier's aluminum stock flow or connections so I'm not trying to create a problem, just looking for some compromise in your choices?

Yes 0.187" ( 3/16") is enough for the keel and please notice it is the same thickness (net) as the original keel? This design is just boxed in or hollow where the original is plate but the net thickness is the same.

Since the keel is so thin and long in regarding its triangular shape (Profile View) I see no reason to even consider the keel sides being one piece. I have not problem if they were three pieces cut completely from the off cuts of other sheets. If the aft dept is say 2' (?) and the length is 12-14'? then finding three pieces per side of these very narrow shapes seems like they could come off the bottom sheets sides forward where the orange peel shape of the bottom leaves the long narrow ends of the original sheet outside the bottom's shape? Butting pieces together to make the keel's box shape is not structurally problematic especially as the entire shape is air tested for insure weld integrity and water tightness.

I'd like to remark about the photo posted. First, my remarks are not intended to find fault with you or to cause offense, you know that the first boat is a fairly steep learning curve so please accept the remarks as corrective suggestions not flaming you.

Look at the port upper most long, that is a good pretty fair curve, I'm not sure how it was fit or applied to the framing? But if I compare that single long to the others, I notice the others, including the chine bars all have angle points or "hoggs" at the ribs/frame intersections. These angle points are not going to make fitting the hull plates/sheeting/skin very easy and depending on your layout technique will result in a very unfair hull.

I know some of these angle points are planned to be replaced by new material so the new photo should help confirm at smoother shape when that work is done. I'll make some remarks about the chine bar as well.

The bottom and topsides can be placed on the framing and tacked edge to edge if the outlines of the hull panels are fair. If they are not layout and cut fair then the chine, keel and or sheer may be hogged, and unfair.

You will need to take great care taking off the hull panel outlines in order to be able to plate this frame fair. You may want to consider a plate model, or a fairing technique to correct the incorrect shape information already shown in the chine bar? Also you'll want to see if more of the longs can end up looking like the upper most port long before leaving the longs and moving to plate work.

Cheers,
Kevin Morin
Kenai, AK
kmorin

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Re: Double Eagle Build

#29

Post by Northeaster » Tue Sep 30, 2014 5:39 pm

Hi Kevin,

Thanks again for all of the detailed info and help.
- I would like to do the topsides in 5/32 but one supplier cannot get that thickness in the 20' lengths and even if my other supplier can get it, I am faced with the roll change charges of hundreds of dollars per sheet, if only ordering 1 or two sheets. (It is basically split among the number of sheets you order in that size). You likely don't face those charges, as it seems 20' lengths are stock in your area. But here, I will pay a large premium for every different thickness I order in the large 20' lengths. It will be enough that the 2 sheets of 5/32 will likley cost more than having 2 extra sheets of 3/16" ordered, despite the extra weight. I will have to look at my quotes and call the supplier again.

re: the photo and resulting comments - I only take your cpomments as constructive, so don't hold back. However, that is not a pic of my build but rather that of another fella, who is buiding a different model of Glen-L boat, and he and I had been exhanging info/ pics. I only used it to show how his plans differ from mine in tha this use a "swath" cut along the edge of the frames, where the longs are free to move laterally and "find" their lines- whereas in my build I cut the slots first and tried to fit the longs along those lines.
He did get it plated, but I am not sure how much trouble he had.
I believe he had tacked or welded most or all of the longs in place to the frames before that pic, which I believe you and others do not recommend until the hull is on, and then go back and wled the longs to the frames, correct?? Would this have reduced those "hogg" spots or what could he have done to better avoid this?

kmorin
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Re: Double Eagle Build

#30

Post by kmorin » Tue Sep 30, 2014 11:43 pm

Northeaster, I'm glad that's not your hull in fact it does have some serious flam in those forward frames a little wide beam forward than the DEagle? I'm not going to try to get to deep into the longs' cut outs, I'd say if you're using angle, they will probably overlap/cover/coincide with the original slots? If so, then make square cut outs for them by laying them inverted to find their 'lay' on the frames.

The hogged lines of the longs in the previous image are from lots of causes, since its NOT yours I'll leave them be. When you start to put in new longs, don't put huge wide notches, the longs won't 'find their' place, they need to be placed in a given location. Are your longs on butt lines or diagonals? or does is show or say in the plans? If they're on butts they'll be straight (in Plan) and parallel to the keel; if they're on diagonals then they'll be lines in the (Body Plan) cross section view. If they're not on either then fitting them as you did to fair the notches earlier is the best method you have handy.

cheers,
Kevin Morin
Kenai, AK
Last edited by kmorin on Tue Sep 30, 2014 11:45 pm, edited 1 time in total.
Reason: typo's
kmorin

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Re: Double Eagle Build

#31

Post by Northeaster » Thu Oct 02, 2014 9:44 am

Hi Kevin,


When I said the longs would find their place - I meant that they would do this, using your previous advice, of clamping the angle down against the frames and attempting not to overly stress or bend them, as they are incrementally clamped to each forwward frame.
Part of my problem, in addition to being a new and ignorant builder, is that my plans only showed (to my knowledge) the placement and/or spacing of the longs in the aft and mid stations, where they ran fairly parallel to the keel and chine. Then there where then instructions / notes to keep them equally spaced betweem chine and keel in forward sections, for example. This is when I erred and cut slots as these locations and naively thought they looked better running / tapering towards the keel/stem, instead of running toward the chine or gunwale. After being shown tha these longs were not on the same plane as my frames, I followed your advice and used 1 1/4" angle (all that i had on hand) clamped down at each station to find the proper location for the longs / slots as I moved forward. I can just enparge these slots, as you suggest, to accomodate the angle. However, I still have the originally cut slots a few inches away, that would need to be filled/ repaired, and hence I thought I would just cut the 1.5" swath out along the edge of the frame, as per the other pic/ design. Also, I did not originally drill holes at the inner end of each slot, so I thiough the large swath would elimninate the need for this, as te hslots would be chopped off, leaving a stress free new surface. But, this does then take away one side for welding, as there would be less contact between the frame and long at each point.

I do not have a recent pic - but sicne the pone below, Ihave several other slots cut on frames 6 and 7, and that's what I was hoping to "clean up" by cutting a large swath per the other pic/ design.

I do not have the plans on me now (1.5 hours away), but have a few pics and on the one below, I may have missed or not checked what looks like longitudinal spacing at station 6 (from the keel). May have to blow the pic up a bit to see the spacing. I will not e at the shop / boat for 2 weeks of so, but will check measurements at that time.

Thanks for the patience and any further advice!!!
Darrell
Attachments
IMG_2855.JPG
DSCN1891.JPG

kmorin
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Re: Double Eagle Build

#32

Post by kmorin » Thu Oct 02, 2014 9:12 pm

Northeaster, I don't see any longs shown in the plans? I see stations/sections, buttock lines/ parallel the keel and I see waterlines but not one single long? I think lining them (longs) off with each frame is a good step but don't see anything in the page you've posted that implies anything to do with longs??

I could be missing something the pic is small but seems clear this is a lines page and not a building plan page?

cheers,
Kevin Morin
Kenai,AK
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Re: Double Eagle Build

#33

Post by Northeaster » Fri Oct 03, 2014 6:41 am

Hi Kevin,

The longs are shown (called bottom stiffeners on plans) at each station, per pics below. However, they only tell the spacing at 2 frames ,I believe transom (station 0) and station 4 (top pic below). At station 4 it gives approx bottom stiffener placements and mentions that the measurements decrease forward of that...but not how much. In addition, the only other info I found on where to place them was the notes to keep them equally spaced betweem chine and keel and between the sheer and chine, in forward sections, on the side of one of the drawings.
Attachments
IMG_2838.JPG
IMG_2833.JPG

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Re: Double Eagle Build

#34

Post by Northeaster » Wed Oct 22, 2014 6:07 am

Hi Kevin - another novice question, but as I am familiar with the lead ballast in my sailboat's keel, for stability / self-righting- and keel for tracking / avoid leeway/ slippage, etc.
Is there any ballast or other matreial put into a box keel if changing from a plate keel design, as we are doing?
I doubt we would add much ballast, as unlike a sailboat we are not trying to have a large righting motion, and likely don't want to add weight, sink the waterline farther down ,etc.. But, I would thinks that adding an air filled box keel would provide buoyance low and therefore some form of instability / tendancy to roll, etc???

Darrell

kmorin
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Re: Double Eagle Build

#35

Post by kmorin » Wed Oct 22, 2014 4:17 pm

North, work out the displacement of a 3" (for a guess- not measured yet) average thickness keel box of the triangular Profile area, minus the log and subtract the wt of metal, log, shaft prop, rudder and gear.... I'm not sure the negative righting moment of the hollow keel is of much concern in the stability equation?

If you list the materials' masses versus the buoyancy you'd have a figure to compare if this void would upset your skiff?

Cheers,
Kevin Morin
kmorin

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Re: Double Eagle Build

#36

Post by Northeaster » Wed Oct 22, 2014 6:12 pm

Hi Kevin - Ok, I guess it would have to have a considerably larger average width, in order have enough air volume to make a difference. I was thinking of the 45 gallon plastic drums under my dock, and think they float about 400 lbs each.

Box keels are new to me, but with your experience and knowledge - if you don't think it will be a concern - I won't lose sleep over it.

Just packing up / closing cottage this weekend, so hope to start back on the longs next week and then order the hull sheet soon.
Darrell

kmorin
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Re: Double Eagle Build

#37

Post by kmorin » Wed Oct 22, 2014 9:53 pm

North, I use about 62.4 lb per foot cubed to figure displacement in salt. So a keel that may hold two (or maybe even 4?) cubic feet is only going to lift 240 lb. or less. The log, shaft, plate, shoe, rudder and all will probably weigh in that class as well. Net; zero flotation from hollow box keel, unless it were of different proportions.

Its never caused me any problems before and they were somewhat larger than this one.

Cheers,
Kevin Morin
Kenai AK
kmorin

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Re: Double Eagle Build

#38

Post by Northeaster » Sun Nov 02, 2014 4:35 pm

out for about a month with a partial bicep tear- unfortunately. Will resume build when I am able.
Darrell

kmorin
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Re: Double Eagle Build

#39

Post by kmorin » Sun Nov 02, 2014 7:00 pm

North, I can't say I'm having any muscle tears but I have been learning how poorly older joints can behave if they decide to bind up. Bursitis, Arthritis, or whatever is going on in the joints of this old carcass are all giving me a full spectrum reminder about what the word pain means!

Whenever you're ready to discuss more details, just post up and we'll see if the bloody fingers will still draw and type!

Hope it heals well, and rapidly.

Cheers, (believe I am raising one regularly)
Kevin Morin
Kenai, AK
kmorin

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Re: Double Eagle Build

#40

Post by Northeaster » Sat Nov 08, 2014 6:11 pm

Kevin - while I am on the mend, I was thinking of making up some custom extended length vise-grip style clamps. Thinking of welding onto existing old and new Vise -grips.
I know I have seen some of your pics of useful clamps, but can't remember on whihc forum or thread... Woudl you have any pics handy you could share?

Darrell

kmorin
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Re: Double Eagle Build

#41

Post by kmorin » Sat Nov 08, 2014 6:24 pm

North, I've purchased or traded into all the pairs I have, all based on the 'bowlegged' visegrip plier. I have some pairs modified for different jobs but in general I use these three sizes.

http://www.staples.com/VISE-GRIP-The-Or ... uct_792130

http://www.amazon.com/Hanson-VIS9SP-C-C ... B002XMWEYI

http://www.amazon.com/Vise-Grip-18-Inch ... PGV5HBC0XE

Cheers,
Kevin Morin
Kenai, AK
kmorin

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Posts: 39
Joined: Mon Mar 31, 2014 3:33 pm

Re: Double Eagle Build

#42

Post by Northeaster » Thu Nov 20, 2014 12:22 pm

Thanks Kevin - I shop on-line somewhat regularly, but hadn't priced clamps. Saved over 50% buying few each of the 11" regular and 11" extended clamps -over buying local. I like to support local, but not at double the price...

Arm improving but a couple of weeks still before I will be able to lift worm drive saw or work much. In the meantime, re priced hull sheet and based on previous discussions, and my lower welding skills, I am leaning towards going with 3/16" material. Local suppliers cannot or will not bring in .160" - 5/32" sheets - they say they cannot get them from their suppliers and I feel 1/8" is too light and would make welding too difficult, but would be significantly cheaper!

Options are:
480 sq feet - 4 sheets of 6' x 20' 5083 h116 $4400 plus tax
500 sq feet - 4 sheets of 4' x 25' 5086 h116 $5200 plus tax
500 sq feet - 5 sheets of 4' x 20' 5086 h116 $4900 plus tax

Things I am considering are:

- boat is 25 ft long so 25ft sheets, would mean not having a butt weld near bow or stern - for looks and ease of welding / heat distortion.
- hull "panels" are less than 3' wide from keel to chine and less than 4' wide from chine to sheer
- I have read that 5083 is harder / stiffer. but how much would I notice for the savings
- can get extra help occasionally but will usually just be myself and 1 helper to move sheets around and place.
- off cuts/ scraps will be used for box keel and floor / sole.

I would appreciate your thoughts on the choices!
Darrell

kmorin
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Re: Double Eagle Build

#43

Post by kmorin » Thu Nov 20, 2014 2:54 pm

North, I'll make some comments which I hope are constructive but surely aren't the last word in regard tool use.

First, I typically cut almost all sheet with a Bosch jigsaw now days. The reason is the control. I can control the cut best with the small blade which will do up to 1/2" with decent speed and great control. I use the aluminum blades, the circular blade path setting and spray the blade with generic frying pan spray on a four count... it works fine. I mark the cut line with both marker and scribe, and I use a halogen light facing me while I cut in order to make a reflection on the scribe which is in the black marker background. I wear glasses inside goggles and have UHMW tape on the saw base to slide better.

I have used a skill saw in the past for plural decades but, its more work, and I can make bigger mistakes, so crawling on sheet in my 60's with a hypoid saw is not as attractive as using the little jig saw (Bosch only).

Next about suppliers. Since we're close to the mills, relatively speaking, we usually don't have problems getting what we want so hearing about 'we can't get it' sound more like "we don't want to bother" than they can't get the material. But moving up to 3/16" should be checked against your overall design wt versus what will happen from this added hull wt?

I'm not saying the 1/8" is too hard to weld, but you should practive on that thickness for a while, if you don't have to make the buying decision soon. I don't think you will be as happy with decisions you make while 'boxed' in, as you will with decisions that are made after being fully informed. The thickness decision should be made after you find out there is no way to learn to run quality 1/8" beads, not because you're making assumptions that you won't get that skill up to speed? Thickness of the design and the alloy of choice should be paid respect that is only changed when you're fully informed, not when you think there 'could be' and obstacle.

So find the all up wt of the hull in the design, compare to your changes and find out what that does to the waterline, and how much the wt will be ABOVE the waterline..... since that will affect the roll stability a bit, and it important to consider. In other words, what are the factual implications of this design change? LIst them one against the other, pro- easier welding; con- more wt.; con-more cost; pro- fewer frames(?) if they're already made...? and so on... this will help make an informed choice.

Alloys, 5086 being more expensive is news to me... but then I've not used it for any boat I've built. I've used both 5086 and 5052 and using the softer '52 as and example when compared to '86 it was noticeably more flexible when finished with the same framing, so we went back into the '52 hull and added a few 'panel reducers' or external longitudinal rails in order to reduce the frame panel sizes left unsupported. So... if '83 were used, which is supposed to be noticeably stiffer than '86.. it implies you could reduce the hull longs and framing centers for the same stiffness of final framed and welded boat.

Since, I think ? you have the frame mostly complete the use of '83 implies you'd end up with a stiffer hull with higher overall strength since it is old enough that it was likely designed for 5052 hull sheeting? Therefore the use of 5083 alloy hull material on a frame designed for softer and weaker 5052 implies a much stiffer final product.

What are the draw backs? (First, all these remarks are to do with the forward 1/2 of the hull because in most planing hulls the stern sections are a reasonably parallel-edge prism shape and therefore easy to plate.) The stiffer plate may be more work to pull/clamp/form/conform to the framing in the bow as the 'orange peel' of the bottom panels are pulled to the frame; due to the high stiffness and greater bending resistance of the 5083 alloy. How much harder to pull in? I can't say but I will remark that 5086 is twice the effort that 5052 requires to pull the same shape together for tacking at the keel and chines. So if that is true, compare the '52, '86, and '83 tensile strength charts and see if you can come to some approximation of 'how much harder' this work will be?

The frame will help you in this work, since you can clamp from a sheet to the frame.

Since this is a first welded aluminum boat, I'd have to recommend that the long sheets be purchased to avoid transverse seams. They are not that hard to build, but for a couple hundred dollars you can avoid them completely by ordering the longer sheets. I don't want to appear confident of a new builder doing sheet butt seams, I'm just thinking you're facing enough learning curve as it is, the extra seam is just dollars; if you can afford them save the extra work.

Do you have panel outlines? I'm not questioning the bottom panels being 3' x length sizes, just saying that topsides often have a fairly large curve forward and end up being the next width sheet (3' becomes 4' wide and 4' becomes 5' ) due to the bow spoon or flam of the topsides in the forward 1/3 of the hull.

If the plans set did not provide hull panel outlines, how will you be developing those outline shapes or curves?

I can't quantify alloy hardness in any way that I can express in comparison regarding "notice for the savings"? too subjective for me to discuss in a first boat project.

Regarding sheet handling, I used to move sheet by hand when I had use of a crew of young men, but now I don't have either young men or a crew so... I made sheet handling equipment.

Image

Image

This is a steel pipe truss end leg(s) and a scrap short I beam cross bar so the chain fall's trolley can roll on the lower flange. They have allowed me to handle sheets by myself and with ease if I had one helper. Not a hard or expensive build (I know on threads like these we tend to spend your money freely!) and the side trusses unbolt from the end plated I-beam so these can be broken down and stored. I could climb the trusses webbing pretty easily and get to rigging at the I-beam or add lifting hardware.

Balancing/lifting a sheet under this type of A frame allows it to be laid on horses to layout, batten and cut and fair, then to be placed on the inverted hull framing and kept in place while working to clamp the sheet onto the frame. These A frames would also roll the frame once plated, so these gantry frames have their uses. My old carcass simply won't do the work it did, so this is one of the tools I built to give me the hands I need.

Hope to be of some help in your considerations for you continuing build?

Cheers,
Kevin Morin
Kenai, AK
kmorin

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Joined: Mon Mar 31, 2014 3:33 pm

Re: Double Eagle Build

#44

Post by Northeaster » Thu Nov 20, 2014 4:20 pm

Kevin - I always appreciate the detailed responses you give, but fear I will tire you out some day with all the questions.

re: cutting, I do have a good jig saw and aluminum blades and have used it some while cutting out the frames, spraying to keep cool / chip free as I go. I am really comfortable with my skill worm drive saw, but undertand that it is a bit less accurate when trying to stick to a line.
I follow your previous advice, and use a marker and then a scribe for my cut line.

re; possibly going from 1/8" to 3/16" - The builder's general notes recommend against increasing hull thickness, but I have stretched the design the acceptable 10 %, or slightly more, and this has spaced frames out an additional 4". I feel (without having numbers to support it) that going from 23' to 25', adding 2 ft more buoyancy in the center of the boat (8 ft beam) shoudl accomodate somewhat the additional weight.
I have aksed for advice specific to this question (going up in hull thickness) on the boatdesign.net forum, and have received advice from yourself and others, mostly feeling that the additional weight would be acceptable. I am not planning a cabin, or at leats not the 1st year - CC only, but may decide to add a small cabin later. If not, there is a weight savings there.

re: suppliers - I have tried all 3 local (within a few hundred kms) suppliers, none of whom stock 20 - 25' sheets, and they all say they can't get 5/32" from their supplier (who cuts from rolls), likely in Montreal. They likely all use the same larger supplier. I think 5083 is just less expensive due to lower margins with the particular local supplier.

re: panel size - I will check again, but I check when rough estimating sheet sizes / quantities required, and didn't think any panel was wider than the 3 or 4' stated, even as the chine or sheer rises - I may have only measure at various points though and may not have accounted for the fact that the sheet will not lie straight, as it wraps around the curves of the boat.

re: hull patterns - none came with the plans. I was disappointed, as the plans advertised full sized patterns, but this was just for the frames, so no lofting was required.
Anyway, I am planning on 1st using cheap 1/8" "meranti" board / cheap plywood, placed end for end and then battened together, to get a rough cut. I am open to suggestions, but had planned on then temporarily placing the sheets in place and shaving off what is required to get the fitup good, likely with a makita hand planer.
Of course, I have never done this before, and the plans / building notes really did not go into any detail in how to actually pattern the hull pieces to come out the correct size / shape.

re: design - this is an older design in plywood, but I don't believe it was originally converted for 5052, as i think it was a reasonably recent conversion, ie, 10 - 15 years ago....of an older wood design. Plan notes recommend "marine" alloys like 5083 , 5086, but do say you can use 5052 as well.

re: material handling - we have a backhoe handy, for when it makes sense to move large / heavy objects and I can call in a couple of friends, if I have a big day of placing hull panels, for instance.

kmorin
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Re: Double Eagle Build

#45

Post by kmorin » Fri Nov 21, 2014 2:27 pm

Northeaster,
I'm just done soaking my hands in hot water so they can stand up to the grueling typing answering your questions! Not to worry about asking what you don't already know, AAB.com's Forum is dedicated to trying to help people just like you who are taking the step of building their own welded boats. I am glad to offer the records of my mistakes for your reference as go, hoping you'll avoid at least those I've already made?

This post is to bring up the topic of paneling/plating/sheeting/skinning a boat frame, so I'll post some remarks to give some reference to you planning.

First is the frame; there are methods to 'check' the frame's surfaces before any pattern fitting is done. The reason to check the frame is
#1. layout and cutting errors in framing can result in the outer (hull inner surface) being unfair and therefore would result in an unfair hull surface when welded to the framing elements.
#2 Welding together frame parts, regardless if they are segments like chine to keel or chine to sheer pieces OR flanges can reshape the frame's outer profile such that the surfaces the group of frames describe are not fair.
#3 spacing frames on an expanded station layout, as I understand you've done here, can also require some re-lofting to fair the locations over just fixed measurements.

None of these possibilities is fatal, but checking the framing for 'fairness' is worth the time before patterning hull panels.

I use two different sets of aluminum pieces to check frames' (and for the record I don't build with frames regularly) outer surfaces. I use angles as we've briefly described above when discussing the notches for longs, and I use pieces of or strips of plate or even flat bars as the other tool since the angle extrusions have some geometry differences from flat bars or plate pieces that are narrow and long (40:1 ratio).

The angles have to be considered in two areas of the hull, as will be true for the plates. All the fairing of the aft 1/2 of the hull is somewhat more critical than the forward 1/2 because the forces of bending the 3/16" material forward will 'fair' that material much more than the after 1/2 hull where lines are mostly parallel or nearly so; therefore very slight 'hi-lo' from frame to frame easily distorts the sheet which is not under any significant tension to "lay-too" the frame edges or longs.

The first test I'd make is to put the angles (full length and let them hang over) along the buttock lines but not bother trying to bend them all way to the chine, the initial focus is on the stern. Then mark high spots, and low spots, coloring with two different markers. Put a dot at the beginning and end of these out of fair locations and draw a line on the frame edges 1/2" inside the hull when the battens are removed.This suggests the sanding fairing work, but is not final. It may be easier if a smaller cross section angle extrusion is used for the bow's more highly curved shape?

Next, do the same exercise with the angle battens but the orientation is 45 deg to the keel, and mark as before, (separate colors OR dashes to show the different sets of information) so you have more or less defined proud spots and low spots in your outer frame edges, and the second process will define the long's outer edges if they are high or low.

Most low spots on longs can be pushed OUTward to the hull plate/skin/panels when the weld-out comes so filling in these is not all that important at this time. But... high spots on longs are different from proud spots on frames. Longs can usually be bent or flexed in but frames rarely can and should be sanded/Vixen filed to fair the higher areas.

The same method can work for the more curved bow framing area, especially the forefoot of the boat where the bottom panel's 'orange peel' pointed curved shape will be pulled in to touch edge to edge with the keel or the chine. IN this area, smaller angle extrusions may be needed to avoid kinking or permanently bending, but you probably already know that?

In both sets of checks there should be some frames in common so; if work station stern to #5 aft, then work bow to #6 so there is an overlap (numbering stations from bow to stern 0-11) of the fairness tests/checks and not a single frame dividing or separating the two fairing check work areas.

I'd set a rule of thumb target of how much to take off any frame as 1T of the plate of the hull and I'd take the sanding of ANY high spot as done in 3 lifts. I'd take all areas down 30% at first, then the next 30% ONLY after checking the 'lay' of battens, and finally last 30% of any high spot after previous checks (both directions) confirmed the need?

I would also consider a Vixen file more likely tooling over a power planer or belt sander.

Now to the plate tests (before sanding or fairing frames). The reason to use a plate of 6" x 20" or a flat bar of 12' or so, longer is better but will work in halves- is to simulate the sheet material's lay without the reinforcing vertical leg of the angle extrusion. Especially useful in the forward end of the hull, where curvature of the wider flat bar/shear strip helpfully simulates the hull sheet, a flat bar/shear strip will flex easily in the vertical but is rigid, like the hull panel in the horizontal deflection. So while the bar will 'lay' to the frame pretty easy, it won't bend out of line at all.

Most important at this point is to understand the bar/strip will not lay on the hull either in a waterline, a buttock line or even a decent diagonal. (read that again, and make a sign to the shop wall!) Please remember this fact; very likely the strip will only lay on the hull from just below the chine at the keels' curve into the forefoot and angle aft and outboard toward the outboard transom corner away from the keel.

However it will work to tell you about the fairness of the surfaces both longitudinal AND transverse as you prepare to take off an outline pattern.

Hope this initial set of concepts helps you to visualize methods that allow you to check the frames for fairness?

I agree, but have not worked out the numbers to be sure, that the increased boat size will accept the thicker plate without problems based on the 16 ft^3 amidships (~1,000lb of buoyancy change @ 12" waterline), I'm just encouraging you to do the figures before making corresponding decisions.

I can post a method of taking off the panel outlines that I've used in the past, to give you some food for thought. It works but is a little easier than full ply panels even though they too will work. I think I have the images already done (?) as part of another discussion in the past?

One question; does this design call for a chine bar (round bar between the topsides and bottom chine joint?). I have seen several Glen-L designs with this feature and have to voice my argument against them every time! They are a truly mixed results element if there is one, so I'm just recalling if we've already covered this aspect?

let me know if this has been vague, there are quite a few ideas to consider and review at this point of the hull. Also I think the keel's shaft log and stern post should be done (at least tacked) before plating the bottom or at least allowances for some of their supports; not the keel sides just the hull penetrations and their vertical supports.

Cheers,
Kevin Morin
Kenai, AK
kmorin

Northeaster
Posts: 39
Joined: Mon Mar 31, 2014 3:33 pm

Re: Double Eagle Build

#46

Post by Northeaster » Sat Nov 22, 2014 1:37 pm

Kevin - it will likely be a few weeks before I am able to do significant work, but I do understand the methods you have described above, for checking the fairness of frames and longs prior to templating.
I picked up steel to complete my "davis type" jig ends, and may spend time in the next two weeks weling those up, as I can get by without lifting heavy objects with the bad arm. Also anxious to have it be able to rotate, just for fun.

We have corresponded on the chine bar "debate", or I at leats have read your views before. My plans don't call for them, and I don't plan on usng them, but somewhere in the general building notes, it does say you can use them if you like. I will likely have the local aluminum welder, who came by to give me some tips in the Spring, spend a day with me as I start really getting into the fitup of the panels. When he saw my boat (only framed up) he acknowledged that the panels (at the chine for example) could be brought together using different joint types, depending on how far each panel is extended towards or slightly beyond the other. i.e. outside corner type joint if they barely meet each other vs a possible fillet type joint if one panel was left a bit long, likely the bottom plate slightly overhanging the chine / topside panel. I would apprecitate your thoughts on this!!! The guy is an experienced aluminum welder and works out West as a welding inspector, coming home in between work stints. He is admittedly not a boatbuilder though, so he is just considering normal fitup / welding joint prep and procedures.

kmorin
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Re: Double Eagle Build

#47

Post by kmorin » Sat Nov 22, 2014 1:58 pm

Northeaster,

I prefer the inside edge (knife edge to knife edge) fit so the inside fillet is only backed by the edges of the sheet cuts, and the outside is left a fillet of different angles of opening due to the topsides to chine angle int he Body Section at any given station. Where the after chines will approximate 90 deg and the forward chine may be much less; 45 deg in the forward 3' of the chine to topsides seam?

I bevel the two sheets back, that is I artificially open these seams' edges back toward the middle of the sheet if the angle of the opening outside the seam is too narrow for weld penetration I do this will #1 Vixen file, #2 belt sander #3 router all depending on the angle needed, the thickness of the material and the tools and bits at hand. (remember I tend to TIG weld these seams not MIG weld them, just for reference)

My primary reason for an edge to edge fit is that this method controls the shape of the sheets' intersections with the most repeatability and fairness. Any overlap technique can result in some variation of the shape to shape fits, and that can easily translate to a wandering seam resulting in dips or hoggs in the boat. If the boat is not tacked up fair, there is almost no chance of ending up fair. If the seam tack up method is not fully controlled to plus or minus 1/32nd inch, then some hull shape irregularities will be "built in". I find it hard enough to keep a hull fair without adding wandering seams.

The only seam I even consider lapping or T forming is the bottom to transom seam and this only if the lower edge of the transom has been 100% beveled on one side or 50% on both. This bottom overhang aft, works as a trim tab if desired on some hull shapes, as it can be bend downward with a wrench and influence some hull's performance. Another reason is if the hull will have powered trim tabs, then leaving a joint overhang can be a work and design savings. Generally I just use the inside edge to edge fit on the entire boat hull panels as well as the sheer clamp.

This joint 'shows' the penetration and that helps to confirm the welding, also both inside and outside its easily trimmed out or back chipped for the opposite side weld as time comes for that weld schedule.

I'll post images of a method to pattern the panel outlines here in a little while, have to find those images first.

cheers,
Kevin Morin
Kenai, AK
kmorin

Northeaster
Posts: 39
Joined: Mon Mar 31, 2014 3:33 pm

Re: Double Eagle Build

#48

Post by Northeaster » Sat Nov 22, 2014 2:23 pm

Thanks - that makes sense. And I apprececiate you taking the time to find the other images.

One related question, and part of the reason I am building the Davis Jig. I have read numerous posts, articles, etc on weld sequence on aluminum boats, and understand to believe that longs should be clamped, etc but left loose ( not welded) to frames at first. Then hull panels templated, cut, fit and tacked together. Now the tricky part - I have read and believe that all hull seams (starting with butt ones "accross" the boat), should be fully welded before the longs are welded to the frames. And, on top of this, the inside weld should be done first, so that it can (among other reasons) be backcut from the outside (exposing good weld from the inside) and then the outside fully welded.
As my boat is upside down, and it would be hard to weld overhead, under the cramped boat - I assume it would be best to rotate the boat, right side up, once the hull panels are tacked, so I could weld the inside hull seams comfortably and horizontally. Then, flip the boat back upside down, to backcut/ backchip the joints to good weld, and then fully weld the outside joints (following a pattern of course, and doing short welds, backchipping craters / stops before each weld, etc.).

Does this sound correct or am I especially dense today?

kmorin
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Plate Modeling Technique: Old School

#49

Post by kmorin » Sat Nov 22, 2014 2:32 pm

Northeaster,
I thought I'd posted this set of images somewhere here but since I didn't find them easily, I'll put them up again. This series of images are illustrations of a plate model sometimes call the builders' model but clearly we can all see this is pre computer era method of work. What I show is the main steps so if this doesn't make sense when you've looked these images over, let me know so I can try to clarify?

I've used this method to build up to 40' LOA with no frames and the boat measured 40'-1/4" from the inside of the bow stem at the sheer, to the centerline of the top of the transom as it curved both transversely (Body Plan) and in Plan View, so it will work if understood and followed.

I realize that you have the frame up, tacked or partially welded and won't need the modeling portion but for those reading along with these I'm going to start at the beginning to make clear how the overall work method gives shapes from models' framing.

Image

This image has three different Plan View scaled drawings of a hard chine, planing skiff cut out from a set of plans; maybe 2 or 3" =1'-0" or so in scale. The areas of the plans are colored to give the lines clear separation in the image; where the pink is the inner bottom from keel to inner chine, the yellow is a chine flat and the green is the topsides.

The plans are glued to a particle board base piece big enough to hold them flat.

Image

To make a 1/2 frame model in order to 'take off the bottom, chine and topsides outlines, the Profile view of the plans in the same scale is cut out and mounted to a carefully trimmed and sanded backing piece of particle board or wood to hold that set of values in the keel plane. This is attached to the base forming a 90 deg modeling fixture.

Notice that the Profile View has a base line ABOVE the sheer some distance to keep the sheer off the Plan View half or above that plane of wood in order that you have working and measuring access to the sheer's points to 'take off' that set of curve defining points.

Image

Just a refinement of the model's overall frame showing the edges of the vertical keel plane Profile View piece is back beveled to allow easier access to the 'knife edge' of the vertical plane for marking more clearly and exactly.

Image

In order to make a 1/2 hull frame model that you can use to find the hull panels' outlines; you'll need to create "station cards" or Body Sections that fit the information on the two Views, Profile (vertical keel plane) and the Plan (horizontal waterplane views). That is simply put a 90 deg cut square of heavy paper, super thin plywood or some other rigid material and mark the vertical and horizontal distances or "offsets" on the card edges.

Next, mark the frames/cards/stations so the keel to inner chine line, chine to chine and then outer chine to sheer lines are all outlines of that individual station- cut the outline of each station and hot glue the card into the model frame.
NOTE again, the sheer is raised up off the horizontal surface in order to make working that edge of the topsides possible where the edges of the bottom along the keel will be easily accessed by the beveling of the vertical (keel) plane.

Image

Once the card frames/station outlines/frame sections are marked, outlined, cut and glued into the plate model frame, you can begin to take off the sheet or hull panel outlines' information.

Several points to make even if they're obvious, they're important. The models' stations must remain stiff, fixed, not flexible in any direction but especially not fore and aft. They don't need to be able to carry wt of any significance but if you can flex them with your fingers and slight touch the frame material is inadequate for the model's purpose. Further, if the cuts along the outer lines that are the hull surface are not clean and smooth then some effort has to be spent to make these edges of the frames smooth. Last this models' frames can be checked for fair just at they were in the posts above.

Next let's take off the hull panels' outlines.

Cheers,
Kevin Morin
Kenai, AK
kmorin

kmorin
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Builder's Plate Model; Old School Method

#50

Post by kmorin » Sat Nov 22, 2014 3:19 pm

northeaster, OK, you have all the previous post's work done as your hull is framed and after fairing your framing ready to take off the fits for the three (6 w/ both sides) main hull panels' outlines.

One method is to use a 'take off strip' which is like a piece of the final sheet taken right out of the middle of the plate/blank sheet.

Image

Here the take off strip is blue. Just like you were fairing the hull, lay the strip along the frames, in this case I drew the topsides instead of the bottom but the work and results are the same, and clamp carefully to each frame and overlap the transom and bow stem in the model, or in your frame those parts of the actual frame.

The two views show the model rotated to two different horizontal planes so that the idea of the strips' orientation is clear. The strip will not, as mentioned previously, fit the chine or sheer but there is some diagonal orientation where it will "lay too" the frame.

Image

This image shows the model upside down in what is the real boat's true orientation for the purpose, again, of clarifying the take off strip's orientation on the hull panel; topsides in this illustration.

[I hope anyone reading these posts will recall that these illustrations are of the work method and ideas not necessarily photo realism! they do have some flaws (like the transom modeling which is incomplete) and are intended to convey ideas not to be shown as photographs.]

When the take off strip is flat and fair the frames, make the inside of each frame/station/section on the inside of the strip. Next measure and mark down the distance along each frame from the edges of the take off strip. These measurements are to the nearest 1/16" or even better to the nearest 1/32" if possible. A table of two rows, strip to chine (upper row of distances) and strip to sheer (lower row of distances) is created and each station/frame/body section is marked with a number or letter identifying where they are on the boat- bow to stern.

Image

Now the panel outline curve information has been "taken off" the builder's model it can be put down on a scaled hull plate blank or Northeaster's case; his real world rectangular plates.

The strip is placed on the blank with the station marks up, a straight edge is used to create lines of the frame edges, and during this stage of orienting the take off strip, the strip is just clamped at both ends to the blank sheet so it can be moved as needed. By working the various edges of the hull panel (combining the distances along the lines of the frames) the strip will be oriented so it have one or two points of contact with the edges of the rough sheet. Tip of bow is usually easy since that is a point along the bow stem marked on the inside of the take off strip. Then the lower most aft, chine and transom point is another single point of orientation. Last a by swinging the take off strip as needed the tip of the chine to stem can be located at or very near the lower edge of the blank sheet.

IN this image I show the top most curve point of the sheer aligned to the edge of the sheet and the transom lower corner, aft, above the lower edge. What is important is that the take off strip can be moved around to find these points and conserve the most material from whatever sized sheets are purchased as rough stock. For example some may buy a 6' wide sheet for the bottom and find both halves will come from one plate/sheet/piece of stock? In this case the topsides are shown to show the shape of the bow and how that can influence the width of the raw material size required.

Image

When Northeaster is finished putting a take off strip on his frame, he'll have lines on the strip with distances from the edges of the strip in two directions along those lines. He'll mark the lines (note there are reference set of fore and aft of each frame to guide the 'point' being marked. The point will be between the two extended lines at the distance above or below the strip as it is clamped to the blank sheet/plate.

Then using full sized 25' long drafting battens of aluminum extrusions, the points are aligned along the batten. The batten will not bend to accommodate a 1/8" or even 1/16" error in the curve-(depending on batten extrusion cross section) those errors will be "faired out" or corrected by the batten as it is 'best fit' to the points. This image shows a rough idea of how to use extrusions as battens to fair a set of points.

MODELING REFERENCE ONLY

Image

If you're modeling the plates of a hull, and you can go directly from the model to the full sized hull, then this illustration is a key point to converting/scaling/fairing the hull panel outline. Northeaster can skip this image as it doesn't refer to a step he needs.

The purpose of a hull model of a few feet in length is to find the hull panel outline shape (curves) without having to put full sized patterns of ply or sheet goods on the hull. The scale model provides a set of curves that are valid in full size but you will have to scale them up to full size AND RE-FAIR the lines (or curves) resulting from the take off.

To do this, I've shown a rectangular grid superimposed on the curves developed by the take off strips' lines and distances. Once the frame and take off strip information is battened FAIR, then a grid is superimposed to use for scaling. The new table that is marked and recorded is the distance above baseline (one side of the sheet for both curves' references) along the 1' spaced grid.

Now when this information is laid out on the final full size plate/sheet/blank the grid is full sized, the distances are real not scaled and the points to be battened are those of the grid, not the take off strip's details scaled up. Then using the batten(s) of different cross sections as needed for the curves, the points are faired to clean curves, highs and lows and other marking or measuring irregularities are corrected and the full size hull panels can be cut accurately.

Image

What would result in scaling up a plate model take off is a grid ( one foot grid shown) with points located a measured distance from one side then battened fair to correct scaling errors, measurement errors and corrections of curves that may not be completely clean.

North, hope this adds up to a clear description of a work method you can use to take off your hull panel outline from your framing? If not- please don't hesitate to ask for more clarity and I'll try to clear up what I may have left vague?

Cheers,
Kevin Morin
Kenai, AK
kmorin

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