metal boat kits.com?

[bkcorwin]

Does anyone have any experience with metalboatkits.com? I am interested in their 16' skiff. I like the simplicity of the design in that theres no raised floor, its just a simple hull and seats. I was just looking for feedback regarding the designs from this company.

thanks
Brian

[kmorin]

Brian,
I've not built the kit from this company but I can make some remarks about the skiff from looking at the plans.
The skiff has a nice bottom shape, in that it transitions from a (deeper) V forward to less V aft and that means, for its weight, it will run into a little wind chop without pounding your eyes out.... but like any light wt. skiff of this class if you push this hull fast enough the waterline it will move aft and the skiff will pound.

I'm not positive but I believe this skiff comes under the level flotation regulations (<20' LOA) of the CG; so the skiff will need foam inside the seats? I'm not saying this can't be done well, but the idea of putting foam in then welding on the voids/seats seems like something I'd prefer to avoid if I could? This all hinges on the kit requiring foam blocks or poured in to the seats, and I'm not positive that is the case with a CG designated 'home-built' skiff kit? I'm assuming it is but if not... then please ignore this concern for the boat on my part.

I've seen some online photos of the skiff completed and in one or two stages of construction so it doesn't appear to be too complex a shape to build? I'm not sure of the level of detail the plans package provides to a new builder? So checking with them on phone calls or costs of calls would be important in case you run into something you're not clear about?

One consideration is that aluminum welding (MIG) is implied and the few photos of this build I've seen were of builders who did not spend time becoming proficient enough in that skill. The welds I saw were proportionally too large and therefore the hulls were somewhat distorted due to the low skill and lack of experience. I'm not aware of the level of preparation you have in regard welding skills? (but) I'd say this was the critical path to successful plate aluminum construction, so a word of caution if you don't already weld? Practice is important before you weld on the boat.

Cheers,
Kevin Morin
Kenai, AK

[bkcorwin]

Hi Kevin,
Yeah the simplicity of the design is what looks appealing to me. The weight specs are pretty light, and given the estimates I've seen on per pound cost for supply and cnc cutting, it seems rather affordable. Can you think of similar designs I might consider? I am pretty confident in my ability to deal with the assembly. I've built quite a few other complicated structures in my time.

I will check on the CG regs. I am unsure about those.

I do not have the spoolgun for my miller 211 so I would not be mig welding. I can pump out about 200amps of AC current and was planning on tig welding the entire thing with 5356 filler rod.

[kmorin]

bkcorwin,
I don't know of other plans packages but I think the SpecMar guys (Stephen Pollard sp?) http://www.specmar.com/ offer this type of work so getting a package from them seems like a consideration? John Simpson http://simpsonmarinedesign.com/ may have cut files for some of their designs? Michael Kasten http://www.kastenmarine.com/ seems like he's done some smaller hulls but I'm not that intimate with his catalog? I'm somewhat familiar with Bill Lincoln's work at http://www.responsemarine.com/bkgd.htm where he has a large catalog of work shown online, not sure exactly which ones are small enough for your project(?) but since Response is a builder they'd likely have NC files for these designs?

TIG welding a skiff hull is not really a good idea for some seams and is 'workable' for others. On the outside corners like chines, sheer to guard deck or sheer clamp, and some other similar welds would work with a TIG weld. But... where a bulkhead or deck met the hull in the 'field' not along the edges, that would be a much different weld.

So to see what I'm suggesting as the difference one is making a box using TIG on the outside corners (all seams) of the box. The other is to put baffles into the box to make it a marine tank, where the 90deg T fillet seam is not along the edges of the material. I'm saying TIG in those instances is not very realistic by hand. In a skiff that translates to all or any frames or bulkheads that lay transverse to the keel plane, will be T fillet types of welds and even with a nice fit and full bevel the heat of standard (non motorized wire feed) two handed TIG will usually get too high and distortion almost always results.

I have TIG welded skiffs' seams almost entirely; but use a cold, motorized wire feed TIG torch to however for outside corners TIG will work fine, just be slow. Really not very agile for tack up either, TIG will require much more clamping and fixturing over MIG tacks.

Cheers,
Kevin Morin
Kenai, Ak

[bkcorwin]

I am not entirely sure I see why you can't tig weld in a bulkhead in the field of the hull? Assuming that the bulkheads aren't place something like 5 inches apart. With a short cup and a cut down tungsten with a button cap on the torch and a flex head, it seems like It should be even more maneuverable than a torch with a cold wire feeder mounted to it?

[kmorin]

bkcorwin,

To me... IMO... the issues are; speed of travel of the weld versus the heat of expansion of the weld; versus the contraction; versus the shape distortion and that is why that weld is not done with TIG- unless the weld travels at speeds not useually attainable with hand held TIG.

To answer your question; get some 1/8" plate, 3' wide, x 3' long. Then put a 3'x3' panel up (@ 90 deg) to the middle as a T. The result is a 18" x 18" T with a 36" Vertical Leg and the two 36"x18" sections as the T top.

Weld the fillet on one side, in fact just tacking will be pretty Olympic but to illustrate what I'm remarking about; get some plate and give a whirl? I think that exercise will do more than any verbal explanation. Speed of travel and rate of puddle formation with hand held TIG are the primary obstacles to tacking with TIG and welding out in the 'field' of a sheet.

I'm not saying it cannot be done, just asking that you try it and see if that helps you become more clear about why its not commonly done? Access to the weld area is not the primary concern in my experience, weld travel speed and weld freeze rate is bigger obstacle. Motorized TIG travels rates approach MIG speeds, so the fusion/freeze timing compared to the distortion and contraction ratios are somewhat more like MIG compared to TIG.

I do encourage you to try this simple exercise to learn more about why I mentioned this as a building method questionable practice?

Cheers,
Kevin Morin
Kenai, AK

[keith]

It seems to me that unless you build a jig like Kevin uses to rotate the hull access will be dificult on the inside of the hull. If the hull is sitting upright you won't be able to reach the center welds on the inside from the side of the boat. That means you will end up sitting or kneeling inside the hull and will have a tough time operating the pedal.

[kmorin]

brian,

wondering if you'd gotten time and torch to test the idea of tacking a 3x3 to a 3x3 as a T fillet? The expansion of the 'top' of the T usually makes this exercise a bit of a rodeo; so I was looking for feedback and maybe photos of the progress in that joint's tack up and weld-out?

It would be kind of critical to make sure that the Top of the T was not on the bench but was at or near vertical when the tack up happens, since that simulates the bulkhead to topsides (Top of the T) that is in question.

This weld with TIG would apply to the seat box 'folds' in the interior used as thwarts in the original design linked above.

Let us hear from you?

Cheers,
Kevin Morin
Kenai, AK

[ReelSong]

The original boat I built , Reel Song II was a modified version of an MBK kit. Rick was very good to deal with during the build. My 2 cents