Newbie introduction

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BKFabricationllc
Posts: 14
Joined: Sat Nov 30, 2019 11:14 am

Newbie introduction

#1

Post by BKFabricationllc »

Hello! I have a small metal fab shop located on the eastern shore of Maryland. I started my business from my home garage 2 years ago and have since hired on 2 employees and moved to a larger location. We have serviced many industries since I started but I have found that I enjoy marine fab and working with aluminum the most. We are mildly equipped, currently have an Everlast 255ext that I do all my TIG work with but have another 325ext showing up in the next week as well. We also have a Lincoln 350mp on hand with a g225a push pull gun that can really lay down some 4043. I am headed to Kentucky tommorow to pick up our first plasma table as well.

I have aspired in the past year to build our first aluminum hull. We just wrapped up a project refinishing a Valco 22' Bayrunner for a local outfitter to use as a sea duck rig. We repaired all cracks, holes, etc. We did a full transom replacement, fully welded floor, fuel tank, new bow hatches, minimalist center console, the whole nine yards. Although I do not like the thin wall design of this boat I did enjoy it's high bow and lines. I am also a big fan of the zodiac milpro RIBs line.

Would there be any suggestions to a set of plans for a boat in the 19-21' range sharing similar lines to the Valco Bayrunner hull? Would love to recreate what we did on this boat just with a lot more rugged hull. Would love a full 3/16" construction. Also, any recommendations for procuring 20'+ sheets in the North East? Thank you for your time! I will see if I can drum up some pics of this build.

BKFabricationllc
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Re: Newbie introduction

#2

Post by BKFabricationllc »

Hope these photos come through!
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gandrfab
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Re: Newbie introduction

#3

Post by gandrfab »

Very nice and welcome to AAB.

Looks like the fuel tank is in the bow?

BKFabricationllc
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Re: Newbie introduction

#4

Post by BKFabricationllc »

Thank you! Yes the customer requested the tank be placed in the bow to offset his gear weight and the rear mounted console. We baffled accordingly and it is performing flawlessly so far.

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gandrfab
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Re: Newbie introduction

#5

Post by gandrfab »

May I suggest some reading?

Image

Image

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Craigb
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Re: Newbie introduction

#6

Post by Craigb »

Nice looking fuel tank. Does it vent overboard, or inside the hull? The fill location should also be arranged so that any spillage during refueling doesn't go into the boat.

BKFabricationllc
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Re: Newbie introduction

#7

Post by BKFabricationllc »

I did purchase the Stephen Pollard book which is very informative!

Yes the tank is vented via a 5/16" hose up to underneath the gunwale to a filter to mitigate moisture. Originally I suggested a gunwale filler neck but was decided against. I will make aware of overfill concerns, thank you for that advice!

kmorin
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Re: Newbie introduction

#8

Post by kmorin »

BKFab, welcome to the Forum.

You do have to be careful adding welded sections to a super light wt pressed hull form as the weld sections are very much more high mass and less flex where they meet I've seen a few problems if the boat is operated in saltwater with greater than>1/2 load capacity- since a good deal of original capacity is gone to the plate mod's.

The press form hulls, Valco, Bayrunner, Monarch, and others rely on the ridges rolled or pressed into the bottoms and sides for the majority of surface stiffness and often weld or rivet in transverse shapes to help keep the pressed panels in place. This implies the alloys used - stretch formed, rolled, and pressed- aren't in the 5000 series alloys considered "Marine" alloys. Welding different series of aluminum to one another can be a bit of headache.

In general, no one uses 4043- 4093 or any other 40 series filler in the 5000 (sheet/plate) and the 6000 (most common extrusions) alloys; as 4043 is like "bailing wire in a chain": the weak link. The strength performance of 40 series alloys is so low, with such brittleness it's just not used in any plate welded boats- anywhere.

If the tank is only supported by flat bars that have had their perimeter welded (lapped) to the tank top? the slapping, pounding into a head sea may bend those? The section modulus of the bars in that orientation is pretty low and has been reduced by the perimeter welds' heat: if the bars were made of 6061-T6 then they're likely more in the T2-or T0 state now!! If they're 5052 ? say originally H32? then they're softened significantly from that performance spec as shown. Those tabs look like the hold the entire "filled tank" mass?

Let's say that tank is 40 gallons? and weighs 40 lb? 40 gal. x 6 = 240 plus 40lb for a round wt of 300 lb full? In a head sea, when the skiff is planing the momentum of this tank in the down cycle of the movement is 300 lb times the velocity of the vertical movement!! That means there can be some really strong forces pushing the tank downward into the hull. Just a note about flat bars used horizontally - not knowing the rest of the tank bedding or two long on which the tank is bedded.

If the the tank top is not cambered? or etched and painted? I'd be concerned with corrosion from standing water on an surface of mill scale? Maybe the paint prep etched and primer coated the tank along with the hull prior to the new paint?

Not sure of the tank bottom bend radii? (they) Look good - hope they're done with a nose bar and not a knife edge; we had a demonstration here not long ago of some strain hardened and stress cracking of a below deck tank that wasn't etched and had knife edge bends. 5052 is a good soft alloy for tanks - but even that needs a nice soft radius to avoid strain/stress cracking.

Is the gunwale a T extrusion riveted or bolted along the sheer clamp? I can't see a continuous weld but do see spaced fasteners? not sure of the construction?

There are several Canadian firms that I think are online offering cut-kit boats of the size you'd mentioned. https://metalboatkits.com/ there's Specmar! a West coast builder/designer/kit provider and Cope Marine- all provide designs and cut files.

I think the way that works is they convey the cut files to an NC cutting firm in your area and then you supply the metal and pick up the cut package? After you've got the package they supply plans directly to you for assembly, weld out and fit out.

If you're anywhere near Response Marine? I'd suggest contacting them (Mr. Bill Lincoln) as he's a designer of incredible depth in welded aluminum. I do know of a couple of other individuals who offer cut files (I don't provide any of my designs for others) for this size range and would be happy to help you get in contact if you decide to plan a welded plate boat?

Hope your venture works out for you, and you get a chance to build from flat sheet and plate? Welds look good, but you've got to get rid of the 40series filler alloy!!

Cheers,
Kevin Morin
Kenai, AK
self proclaimed AAB Forum "Mill Scale" gnat-zee
kmorin

BKFabricationllc
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Re: Newbie introduction

#9

Post by BKFabricationllc »

Thank you for your advice Kevin! I was hoping you would comment as I have read many of your posts and appreciate the vast knowledge you share so freely with others. As for the tank we still do all our bends on an apron brake at the moment with quite a bit of setback to basically give us a radiused air bend. Our next big purchase will be a 12ft. press brake and I will ensure to incorporate some bull nose tooling per your advice. The tank comes in at 35 gallons full and likely will never exceed 30 gals. We incorporated supports underneath.

As for the welding 95% of this project was TIG'd and we solely use 5356 wire in the rare event we have to have parts post anodized. We are still working on dialing our 350mp in on 5356 wire as it always seems so sooty (assuming because of the magnesium content) compared to the 4043. I will make sure to adhere to your advise and leave the 4043 to non critical repairs.

The gunwales are a t extrusion riveted to the stringer uprights.

Boy let me tell you this 30 year old corroded aluminum was a treat to TIG haha.

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welder
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Re: Newbie introduction

#10

Post by welder »

BK, welcome aboard, we really like pictures here and as usual Kevin nailed it again, GREAT post Kevin.
Lester,
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BKFabricationllc
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Re: Newbie introduction

#11

Post by BKFabricationllc »

Welder, I will see if I can drum up some more photos of my marine projects!

BKFabricationllc
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Re: Newbie introduction

#12

Post by BKFabricationllc »

A few from the past year!
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kmorin
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Re: Newbie introduction

#13

Post by kmorin »

BKFab, thanks for showing more of your work, my remark here is solely bout the last image "_367" showing a TIG bead along a flat (might be beveled?) surface bead.

First, if the puddle is chilled such that is will raise a "rounded" bulge or crown between adjacent puddles? Then you have three events that may need to be considered?

#1 the chill or travel required between 'dimes' indicates the top surface will have stress raisers at the edges of the weld. If the plate sides of this weld are folded up- there can be a notch or 'jagged' edge in the bending area.

#2 If this weld was done with constant TIG amperage (?) then the travel is likely 50% long B) if this was pedal pulsed(?) the high to low is too extreme as there are actual 'saw tooth edges' of the bead's toe and top edges.

#3 if the weld was done with a pulsed Amplitude power supply - the duration of the two ends of the wave are too far apart- OR the amplitude of the Pulse ON high value is too high for the low background percentage setting.

So just a remark that the individual moves/puddles/dimes are to distinct, that indicates a bit too much chill/travel/transition between the puddles or weld pools.

just a note, as usual I'm having trouble with photobucket so I can't link the images as they're apparently too large!!! even though they were reduced to upload and store!

Nice work, hope there wasn't any 40series filler -ANYWhere??

cheers,
Kevin Morin
Kenai, AK
kmorin

BKFabricationllc
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Re: Newbie introduction

#14

Post by BKFabricationllc »

I believe the last photo was actually snuck in from a pressure washing skid. I generally tighten up my dab spacing quite a bit more than that as shown in every other photo. I generally run off a 2t button, button on for whatever material thickness I set my max amps at and button off drops down to 36 amps. Depending on the conditions I travel constantly or will manually pulse to control my heat.

BKFabricationllc
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Re: Newbie introduction

#15

Post by BKFabricationllc »

And this is all 5356 filler. I dont believe I have any 4043 tig wire on hand. I usually buy in bulk alcotec.

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gandrfab
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Re: Newbie introduction

#16

Post by gandrfab »

LIKE.jpg
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BKFabricationllc
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Re: Newbie introduction

#17

Post by BKFabricationllc »

http://www.specmar.com/aluminum-boat-pl ... kboat-1659

Really liking the lines and similarities between the Valco and this Sitka!

kmorin
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Re: Newbie introduction

#18

Post by kmorin »

BKfab, you're remarking about the Profile View lines? Don't see the push boat bow frame on the Valco!!

Of course, you don't have to add the push-boat squared off bow to the hull- you could just build her as a conventional bow. Probably other Specmar lines sets similar to the Sitka w/o the bow push boat framing?

Fairly generic and reasonably traditional lines in Profile and Plan, with the exception of the "Harbor Master's" utility bow.

Cheers,
Kevin Morin
Kenai, AK
kmorin

BKFabricationllc
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Re: Newbie introduction

#19

Post by BKFabricationllc »

Hey Kevin,

Yes the bow is a bit different from the Valco but the more I look at the squared off bow rail the more it grows on me especially considering the end user hunting from the vessel and pulling dogs over the rail, bow fishing platform, etc.

kmorin
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Re: Newbie introduction

#20

Post by kmorin »

BKFab, hadn't thought the boat as gunning skiff but if that's the way it will be used (not as a pushboat) then the bow's wider deck at the stem may well be a good idea?

Don't know? The hull's lines are pretty generic for Specmar and their scantlings are usually "military grade". They do design and build tough boats- so I'm sure a cut-kit from them would follow the same patterns?

Cheers,
Kevin Morin
Kenai, AK
kmorin

Wantry
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Re: Newbie introduction

#21

Post by Wantry »

Kevin, out of curiosity, what do you mean by "military grade..." is that a reflection on durability? or something else?

Anyway, I think that pram bows/squared bows fit the niche of duck boats. It's easier to embark/disembark with the boat aground, easier for the dogs to take a line and jump, easier to hide, a little easier to trailer and launch especially where roads or ramps are lacking. This one looks like it has a lot going for it for a duck boat:

http://www.specmar.com/aluminum-boat-pl ... utback-406

The various LC's, and LC-based hulls, also have a certain appeal. Stanley's Pulsecrafthttps://stanleyboats.ca/pulsecraft/ (and similar boats like Specmar's LC's) are great as duck boats, and the Stanley Predator series ( https://stanleyboats.ca/predator/ )is kind of like a baby LC, with the drop gate and drop gate framing deleted. Specmar offers plans for something similar to the Pulsecraft (http://www.specmar.com/media/1934/21-ft ... ebsite.pdf), but I haven't seen plans for anything quite like the Predator. Maybe someone here has.

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Re: Newbie introduction

#22

Post by kmorin »

Wantry, yes I'd intended to compare to 'way overbuilt' equipment by referring to Specmar's as military grade.

Their scantlings are thicker than needed - needed being a relative term. But the results are very stiff hulls. One of Specmar's kind of signature items is a pair of deck-to-hull full depth longitudinals located about 1/4 Buttock line outboard from the keel.

In some of their boats these things are ( to me) massively thick, reinforced and run from the transom to the 'collision' bulkhead or fully 2/3 the Waterline -sometimes 2/3 LOA!

If built to spec- a Specmar is a very rigid skiff.

Cheers,
Kevin Morin
Kenai, AK
kmorin

BKFabricationllc
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Re: Newbie introduction

#23

Post by BKFabricationllc »

I spoke with a rep at Specmar for some additional info to prepare a quote for a customer on the 23ft. Sitka hull with an open deck and he mentioned they recently had one of their boats involved in a collision with another vessel and their boat near cut the other vessel in half. That's what I'm talkin bout! I would far rather over build than compromise! I do like that outback hull as well but wonder how it would perform in the bay with the flatter bottom?

kmorin
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Re: Newbie introduction

#24

Post by kmorin »

bkfab,
in touching on the bottom deadrise vs "performance" issue you'll end up getting to "ride" as a concept and I'll share some insight.

This is a design helix issue. The design helix is a slowly spiraling upward circle of design decisions that becomes more and more detailed until the spiral ends in a point.

along the bottom few circles you decide deadrise. Then when you get to all up displacement you may decide to 'revisit' down several levels and change the deadrise to get a better 'entry' or softer ride?

After you've gone around this cycle hundreds of times (remember that the first rule of boat building is: "The first couple dozen skiffs are a BIG education") if you design the boats will get a 'feel' for deadrise vs 'ride' or performance.

However, the main problem is: the hull's performance is a series of compromises- not all of them acceptable to any given owner! I've had two identical hulls go out the door, where one owner came back to me with praises and the other yelling like a sailor; things about my mother that were not true!

Beware of the word 'performance', the word 'ride' and the word 'best' when applied to a description of a boats' hull!!! They are definitely vague- completely elusive and that's because "beauty is in the eye of the beholder".

Good performance agreed by one skipper is not necessarily good performance described by another!!

Any boat's ride is a function of the deadrise, all up displacement, sea state and hp to wt ratio. But figuring those variables out, I will assure you, can be a life long task!

cheers,
Kevin Morin
kmorin

BKFabricationllc
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Re: Newbie introduction

#25

Post by BKFabricationllc »

Kevin it seems our customers expectations and perspectives are always our biggest hurdles! None the less if I never try my hand I will never know whether I was meant to succeed or fail! I am hopeful this customer proceeds with this build and if he chooses otherwise I may proceed with it as a showcase for our first aluminum hull as I would love to build a vessel that will stand the test of time for my family! We fired up our first 4x8 cnc table this week but we have aspirations of it leading us to a larger table to service this industry for years to come! They may be pipe dreams but at least we are taking the steps necessary to make them come to fruition. I appreciate all of the advice given thus far, very generous of you all!

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