Vancouver Island Skiff build

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stormsails13
Posts: 3
Joined: Fri Jan 15, 2021 8:18 pm

Vancouver Island Skiff build

#1

Post by stormsails13 »

I'm getting ready to start building a 17' skiff it's a v bottom center console all 3/16 5052 Aluminum.
I've welded most of my life and have lots of experience building in aluminum.
I don't have a lot of experience buying aluminum as most of the time I just take it off the rack where I use to work. So my question is what is the most cost effective size of aluminum sheet to buy and what sizes are usually stocked. Do most people buy 4x8 or 4x10 sheets and but weld them together. Or do you order full size sheets. Was thinking of buying from Russel Metals but if anyone on the Island has a better supplier please let me know.
kmorin
Donator 08, 09, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21
Posts: 1589
Joined: Mon Aug 18, 2008 1:37 am
Location: Kenai, Alaska

Re: Vancouver Island Skiff build

#2

Post by kmorin »

stormsails13,
I'd say that the larger the sheet you can purchase the more 'effective' and 'efficient' the build because you have the same final wt. of material to purchase and less cutting, fitting and welding? Nesting your shapes on paper will show you how to use the off-cuts for transom, decking, or other shapes required of the build.

You can skip the hull transverse seams on the topsides and bottom panels if you start with 20' sheet. This usually results in a cleaner, unwrinkled, nicer looking skiff hull.

If your design calls for a cambered bottom aft, instead of a V, then the 'orange peel' bow 'pedals' can be cut from a full (chine to chine one piece) width piece of plate. This reduces again, the welding by eliminating a weld seem for 1/2 the boat's bottom. If the chine is 5' or 6' wide then a single 5x20 or 6'x20' sheet will make the entire bottom with only the bow's 'pedals' to outline, cut and curl up so they touch at the keel's 'rabbit line'. This build circumstance isn't available in most designs if there will be a V all the way from bow to stern; only in those skiffs where the after 2/3's of the hull are cambered, which is not uncommon on small skiffs of 17' LOA.

A 20' sheet is one size common in aluminum, but I have no idea if your local vendors stock that material? If there are any boat builders in your near area- its very likely the 20' sheets are available at no cost premium? But then, you'd only learn by calling around?

3/16" 5052 for a 17' LOA skiff is pretty heavy so the '52 vs '86 alloy becomes somewhat a moot question. That is; most builders go with 5086 or 5083 for the bottom then maybe '52 above the waterline? but your heavier scantlings (for a 17'er) will insure there is no structural issues with the softer, lower yield alloy.

I'd (propose to ) build a skiff that small out of 5/32"- 0.160"- (4mm) bottom and use 1/8" -.125"- (3mm) for the topsides. I'd MIG weld (0.035" wire) the main hull seams in most skiffs and most structurals and TIG weld the corners (last few inches of any transition in the framing or plating), intersections, and details to make the welds higher quality and more controlled.

With 5052, I'd expect to use exclusively 5356 filler alloys and perhaps a little helium gas mixed with argon for hotter welds and deeper penetration at the 'same' weld wattage as pure argon cover gas.

We'd sure like to see a picture of her lines, and to watch the skiff come together if your build schedule can spare time to share images online?

Hope someone in your area responds to your questions regarding metal suppliers in your neighborhood?

Cheers,
Kevin Morin
Kenai, AK
kmorin
stormsails13
Posts: 3
Joined: Fri Jan 15, 2021 8:18 pm

Re: Vancouver Island Skiff build

#3

Post by stormsails13 »

Thanks for your reply. The plans are a Jimbo skiff from Glen L. I'm going to stretch the boat 10% and keep the same beam which the plans say is fine.

I just have a mig setup so for ease of welding and design was going to just stick with 3/16 for most of the build. I had the same thoughts about the 52vs 86 3/16 will be pretty tough. I think the design calls for 1x1 1/8 angle on the bottom seams also. Using all the same aluminum makes it easier to manage cutoffs for other parts of the boat also.

I'll posts some pictures when I start for the build thankyou again for the advice.
User avatar
gandrfab
Posts: 533
Joined: Fri Mar 28, 2008 12:33 pm
Location: Edgewater Fl

Re: Vancouver Island Skiff build

#4

Post by gandrfab »

stormsails13
Posts: 3
Joined: Fri Jan 15, 2021 8:18 pm

Re: Vancouver Island Skiff build

#5

Post by stormsails13 »

Yeah that's the boat, I should get the plans in a week or two.
kmorin
Donator 08, 09, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21
Posts: 1589
Joined: Mon Aug 18, 2008 1:37 am
Location: Kenai, Alaska

Re: Vancouver Island Skiff build

#6

Post by kmorin »

Stormsails13,
Lots of Glen-L skiffs are clean lined like this garvey. You mentioned there were angle extrusions over the chines and keel seams, are there other angles under the hull between the keel and chines?

IF so? good; they do help tracking with a small skiff reducing the amount of helm, back and forth needed for a V in this size skiff. Also inverted angles on the bottom flats between the keel and chine help in tracking in a turn, which this shape will do very tightly compared to a shape with parallel chines.

The chines taper several inches (don't know amount) in Plan View /top down view so the skiff will heel over much more in a tight turn and therefore will turn much sharper or tighter than a comparable shape with chines that don't curve in toward the keel in after sections of the hull. This fact is visible in the Body Section (plan) View of the hull's lines shown online. Stations 6, 7, 8, & 9 all show the chine tapering toward the keel. Since these stations are all aft the Master Section, you can conclude the skiff will 'tuck' her stern more when the outboard is pushed hard over.

As a result, if you turn sharply at high speed, this shape will skid or slew in the turn if there's no additional lateral resistance below the bottom- so if the hull doesn't have the angles mentioned above it may skid compared to the hull with external longitudinal "rails" in the water.

While the hull is simple in shape, I can understand why Glen-L's family recommends against changing her beam. Not only would her topside panels change shape a little bit, but the engine ht. off the water might shift too because of a change in the at rest and running waterlines due to the changes in beam.

I look forward to watching your build.

Cheers,
Kevin Morin
Kenai, AK
kmorin
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