25' Skiff Build

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Yofish
Posts: 97
Joined: Wed Jul 04, 2018 9:40 pm

Re: 25' Skiff Build

Post by Yofish » Sat Feb 09, 2019 11:34 pm

Forming bottom strake from 1/4"x2"x2" angle. I can't put it on whole which is the easiest way but my ceiling is only 10' so I start with a 9' chunk. It's pointed 5/8" back to full width at 6':

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Must be forced down as the material is too strong to shape perfectly with a short lever arm:

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Yofish
Posts: 97
Joined: Wed Jul 04, 2018 9:40 pm

Re: 25' Skiff Build

Post by Yofish » Sat Feb 09, 2019 11:46 pm

Little details. Making drain for aft compartment. This skiff has five watertight compartments and the aftmost has a 6" circular hatch that is notorious for leaking. This is to access engine mounting bolts:

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Cool! Zincs on and strapped down for to turn again:

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Yofish
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Re: 25' Skiff Build

Post by Yofish » Sat Feb 09, 2019 11:55 pm

Couple more pics of the goom-bah combo dolly/rotate thingy:

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Yofish
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Joined: Wed Jul 04, 2018 9:40 pm

Re: 25' Skiff Build

Post by Yofish » Sun Feb 10, 2019 9:54 pm

Up-n-dicular again! One of my fav milestones in that the hull could be splashed and float, but far from done. Nonetheless, it's always been special to me; kind of like landing a fish.It's exciting as well as satisfying, BUT! more misery dead ahead what with putting the decks on. Now we have not only blades but bars, the deck beams, to bark shins and fumble around. Yes, Kevin is shaking his head as he reads - I'm certain.

I want to talk a little about a couple of things; computer aided design and having learned to build BEFORE computers and how it all got blended into, for lack of a better way to put it, my style of doing it. I got started building in the mid-seventies working as helper for a man that had the first aluminum boat building shop in the little end-of-the-road place that I landed in, Homer AK. It had a great byline -" Homer, a quaint little drinking village with a fishing problem." That was entirely true. The bars and churches were about even-steven. Pretty much, the economy was based on commercial fishing. I have always been haptic, remove my hands and I'd die. My schooling was in art but it was clear to me, after being in Alaska for six years or so, that that wasn't gonna put the frejoles on the table and landed this job. It ended up being several years before the mast but it did ignite something in me. This man had a way of building boats (mosty skiffs) that was intriguing: he had no plans other than a more or less 'universal' parabola (scaled to fit the LOA and breadth of the target build) that he used as a bow cut for to start creating a hull. Then, with a nice batton and his eyeballs he would play with various lines (laying on the floor) until he got what looked good to him for a chine. Then, a side sheet would be lain against the now cut chine and scribed then cut, the drops being used to make the off-side cuts. The same process was used to strike the sheer. Put on a transom and then whatever frames (made from masonite patterns by scribing and joggle) with hull stiffener between them for the longs. I'm guessing I helped build over twenty boats up to 32' in length using this method while I worked for him. I still see them around in use. The work was seasonal as it was nearly entirely driven by commercial fishing. I joined that parade, too.

It came to pass that I became more of a fisherman than a boat builder's helper (WAY more money) and had quit the works but needed to keep my hands busy and those frijoles on the table for now a wife and growing family so I began building on my own using the same method what with what I thought had an 'improved' bent.

Fast forward to the computer age! So, I got bit by that bug but I'm not at this point going to go into all of that now (maybe later), nor will I go into my great admiration for the software I use and the man who created it (maybe later) and instead, focus on letting go.

Man, oh man, letting go of things that are imbedded in your cells is a tough row. To unlearn, I think, is probably one of the hardest things there is. It took me an EXTRAORDINARY amount of time to trust what was before me.

This is getting too long winded and of no practical use to anyone. I present one of the little 'letting go' things that would make a fourteen year old these days laugh out loud. When I began building via CAD, I never really trusted it. I was always, "Yeah, but what if" - this or that - whatever my cellular resistance could come up with.

So, I could never bring myself to trust that the decks would "just fit" given my experience. I always made a shelf (a 5" wide band all the way around at deck level) first, on which even an idiot could land on for the balance of decking. Hey, that's not that much material and better to hack away to make fit at that than a full sheet! Well, after about three skiffs it dawned that the wiggles in the sides (distortions) were not SO savage that they couldn't be tamed?

Here is a drawing of the skiff showing the four principle decks, all landing on awthart frames that are sealed thus watertight. The fifth is not show, that being the transom engine mount:

DECK_2.jpg

Now, a cut view showing closer what can happen after welding the inside chine, outside chine etc. The green line shows what the decks are in computer world and the red line what they MAY be in the after welded world - never the same - sometimes in, sometimes that-a-way. The important thing here is the X's. These are hard points, they are welded to the sides in order to make watertight compartments:


DECK_2.1.JPG

Yofish
Posts: 97
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Re: 25' Skiff Build

Post by Yofish » Sun Feb 10, 2019 10:30 pm

Man, that was a lot of words to describe something that is actually kind of embarrassing, my lack of awareness. Anyway, here is the forward deck that is of the drawing in place showing an unacceptable gap:

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Lucky me, the gaps could be 'jacked out', meaning using a bottle jack to force out the sheet against the side and hard points before striking the cut lines (sheet longer and wider than necessary compliments my still not letting completely go, and wise I might add) and in this case all was inward of the hard points - yay!:

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Believe me, it's not always this easy. Many times after jacking the sheet against the hard points there will be a bow outwards that takes effort to bring home.

Yofish
Posts: 97
Joined: Wed Jul 04, 2018 9:40 pm

Re: 25' Skiff Build

Post by Yofish » Mon Feb 11, 2019 9:15 pm

What a mess! If I could afford the 3 grand for ALL cordless tools (that would require about 20 batts) I'd go for it! And a cordless welder, too....

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The forward decks are nailed along with doublers for the fuel tank mount and 1/2 of the foredecks. A tool and a technique I want to add into the conversation. Jacking one deck when there is something to jack from makes sense and is easy. But we have another side, too. I made this tool out of a cheap-o 18" pry bar by grinding a cam into it so it levers against the one side already in place for to push the other side tight:

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Wow! I got three pics in without gagging!

Yofish
Posts: 97
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Re: 25' Skiff Build

Post by Yofish » Mon Feb 11, 2019 10:37 pm

I made another tool that I'm sure I'll need to jack the remaining decks but I'll wait till then.

SAWING ALUMINUM:

This is, of course, my opinion but using a worm-drive saw for this work is needlessly taxing and ungainly unless one is sawing 1/2" plate all day. The smallest saw you can get is the best for sheet, and that means the much maligned so-called 'Home Owners Saw'. Unfortunately these days that particular saw has burgeoned with awful appurtenances: big knobs, giant feet, and nearly unusable safety devices if one is out of position. Along the way they decided to make them as powerful as a Skil 77 and thus added weight. The green saw in the last set of pics is the BEST saw I've ever used from the work I do - a Hitachi C7, sa, and sc. They are common, still, in asia and other places but not here, alas. I have five and rebuild them. Light, powerful enough, small steel foot.

Anyway, the saw to me is much more than something that just cuts on a line. It is a much more useful tool than that. In certain setups it's vastly better than a grinder in wasting material not only faster but more accurately and way less expensively. Many of these actions can't be done with a 77 because of which side of the blade you're on. Oh! Add this to whatever you chose and you will be amazed. This one of those stupid simple things that I wish I'd thought of a long time ago. Selfstick, hook side of Velcro on the shoe. Yes, some crumbs get imbedded but they do not scratch as you can see. I've tried EVERYTHING and nothing compares, period:

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BACKBLADING:


Here we have what I'm talking about. The foredecks COULD be manipulated as what I showed previous but it's not worth the effort thus I scribe them to fit. Many times the amount to be removed is minute and hard to do cutting forward so using the back side of the blade is a surprisingly accurate and fast way to go, much faster than grinding. It's hard in this picture to appreciate what's going on. The saw is angled to approximate the the angle of the side sheet that the deck abuts and the BACKSIDE of the blade is doing the cutting. In this configuration it is more like planing than cutting using a swift and discrete motion. One can see the small amount of material to be removed by the black pen line:

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Up in the bow, it's important to make the deck as tight as it can be thus the severely angled cut. This helps prevent hot-cracking.

Yofish
Posts: 97
Joined: Wed Jul 04, 2018 9:40 pm

Re: 25' Skiff Build

Post by Yofish » Tue Feb 12, 2019 9:45 pm

Things looking a little more ship-shape up towards the bow:

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TACKS AND TACKS!


Tacks are a big deal. I wish I could give steadfast advice about this but that's not possible. There are too many variables. I can tell you that don't want too many but many are better than not many! From painful experience I'm here to say that one DOES NOT WANT a principle tack to come undone, like, on the bottom central seam, or the decks. For example, in the last pic of the foredeck, if a tack comes undone there is hell to pay. This is because of all the tension of the sheet wanting to boing outwards for all it's worth. When it does happen, only misery prevails.

Yofish
Posts: 97
Joined: Wed Jul 04, 2018 9:40 pm

Re: 25' Skiff Build

Post by Yofish » Tue Feb 12, 2019 10:59 pm

I had wonderful luck in that I did not have to apply any pressure from the outside inward on the forward deck and jacking the sheets to the hard points took out all the boings so the tacking was quite reasonable in spacing making for a comfortable stretch between for welding. Doesn't always happen that way. The tacks were 1/2" or so, straight, no wiggles. Notice the weld goes up to the tack, stops, then the ENTIRE tack is removed before continuing. As I've said, I'm a one-way weldor; meaning, I go in one direction only. I do not hop around from side to side or any other sequencing. This is for two reasons: going one way preheats the material ahead which is a plus. Second, the stops with aluminum MIG are nothing but cheese. Removing the cheese and starting again goes a long ways to make the welds watertight. I've read what I think is nonsense about backstepping, moving about area wise etc. I've never built a steel boat so perhaps there is some validity there, but I've never had a problem doing it this way:

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Tack on the sheer. If things go oingo-boingo on the sheer it's always an easy fix. Hell, you can tear the whole bloody thing off and start again! Not so much other places. Longer tack, especially towards the bow:

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Foredeck tack sequence:

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Yofish
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Re: 25' Skiff Build

Post by Yofish » Fri Feb 15, 2019 9:07 pm

This could easily turn into Groundhog Day what with whats the diff between one and another deck but I'll add a couple of things. First a pic of the aft decks:

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And then another device that helps pushing the sheet into place when one is already in place. It's pretty obvious that this could be made simpler but sometimes a guy gets an Idea Jones that is only satisfactory because you did it. It's a tube that was laying around and there is a blade that runs free in two parallel slots. The blade has knife edge ground into the bottom edge which is kinda important in certain circumstances but I'm not going into that now. As it's being used here, on the off-side sheet that had to be pressed HARD against the hard points because this is the side side shown previously that had the boinger at the sheer; chasing them damn boinger debils! This pic shows the time when the sheet is being marked for final width and slot welds:

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Yofish
Posts: 97
Joined: Wed Jul 04, 2018 9:40 pm

Re: 25' Skiff Build

Post by Yofish » Fri Feb 15, 2019 9:39 pm

Some catch-up things:

THIS IS NOT AN OSHA APPROVED TOOL!

However, it is great for removing tacks. Fundamentally, I have great distaste for grinding with a stone. This blade,

https://www.amazon.com/KwikTool-BB450-2 ... way&sr=8-1

is the ticket. As gnarly as it looks it is quite tame because of a nearly zero degree tooth rake. I will agree that a guard would be safer but alas less handy. From personal experience, I will tell you don't even think about using a normal 4-1/2" woodworking blade! Only because when I was younger and used a flip hood for welding and grinding was I saved from something that could only have been horrific when I used a wood blade, cutting tacks, with a 4-1/2" a grinder inside a tank. One must ALWAYS make sure it quits before laying down. I would never recommend using it but with a paddle switch for the obvious reason:

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The back-blade metode of wasting material, in this case angling deck sheets to the sides:

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The HAZ (heat affected zone) of plasma cutting shown here trimming for width on forward deck:

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Yofish
Posts: 97
Joined: Wed Jul 04, 2018 9:40 pm

Re: 25' Skiff Build

Post by Yofish » Wed Feb 20, 2019 7:48 pm

Last mid-deck pressed to side:

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After a mile of welding another milestone; no more combat gear and stumbling around like drunk. Each piece of deck laid is a heavenly island - except - you still have get down on you knees for long periods. After days of being on your knees, a fellow can get grumpy. From here out it's all relatively normal and not so back-breaking..... Bow view:

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Aft view:

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Won't be too much to see for awhile, I've got to put the gunwales on and a couple more launching points for the cabin forward. I don't like building cabins. In this particular case the client is 6' 7" and he wants to stand while at the helm which is hard over. I recessed the floor more than I ever have which caused some problems I'll discuss at the end when I reveal my boo-boos. If I didn't care, I'd just do a completely flat deck and put an outhouse-in-the-fog on it. You see that all the time and it looks like hell. If you swamp, however, there's a nice swimming pool to play in!

Yofish
Posts: 97
Joined: Wed Jul 04, 2018 9:40 pm

Re: 25' Skiff Build

Post by Yofish » Thu Feb 21, 2019 9:40 pm

Boy oh boy, it's nice to be on my pins only today! The knees and back get a break. Anyway, I rescind that I wouldn't be posting for awhile because the following may be of interest. I use this extrusion called 'G-GUNWALE' that is popular in the pacific northwest. I'm not crazy about it but it's easy to use if one follows a procedure for applying it. It's wimpy being rather thin and is not comfortable to sit on but compared to other ways it gets the job done quickly. First, a pic of a tool mod that really helps with the process. This a Pony clamp that I welded some gnarly cast iron jaws onto. Being that these skiffs have a chine flat they offer a surface for which to use bar clamps but I found that the angle of the sides too many times made them slip their purchase, usually at the wrong time. The upper jaw is not really that necessary in this application but is very useful elsewhere:

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And away we go, aft to fore!

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Before start, I take a short piece of the material and mark every 8" or so for registration. Two other short bar clamps work in concert with the big down muncher, moving no more than 10" at a time and likely less up forward. Clamp, clamp, munch, munch away, slowly, paying attention to the registration marks. It gets slower towards the bow but just keep on trucking to the tippy-tip. Also, one can see the top reg marks, must have bottom edge ones, too:

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Yofish
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Joined: Wed Jul 04, 2018 9:40 pm

Re: 25' Skiff Build

Post by Yofish » Thu Feb 21, 2019 10:16 pm

OK now, a confession about what that violates just about everything I was taught about welding boats. Nonetheless, this is what I do with this G-gunwale stuff: I do NOT weld the lower edge. What I said before about clamping and registration is important to my method in that by making certain that it is tight, when welding only the topside it gets even TIGHTER against the side. Here is a drawing of a typical (but typical is not completely true because the side angle is CONSTANTLY changing fore to aft) that shows what my approach is. When the extrusion is clamped as tight as it can be, and aligned to the registrations, when welded, the weld shrinkage causes a rotation of the gunwale that presses it even more against the side. Now, I would never recommend this for commercial duty, a fishing skiff, barge tender and that sort of thing as an upwards slam to the underside would be untoward. However, for uncle Bob and aunt Millie, it works. This drawing demonstrates the obvious geometry of the matter. Does it absolutely paste itself to the side with nary a gap? No. But generally if done right it's pretty good. What MUST happen is that that 'flat' part of the G must be parallel to the sheer flat, thus all the clamping:

G.jpg

The last skiff I did was a commercial thing and completely different. A split pipe that is un-possible to do this way. Must be welded both sides.

Yofish
Posts: 97
Joined: Wed Jul 04, 2018 9:40 pm

Re: 25' Skiff Build

Post by Yofish » Mon Feb 25, 2019 11:03 pm

During an interregnum of VP (visual progress) I'll riff on some things.

Obviously, I don't use much in the way of props to make the hull conform to a mold, that is, a form like a cradle. I have found that by trusting the geometry that the computer generates, which is nothing more than enough points of reference for to have things come out minnie-jinny. I do not ever level anything. Much like a lathe, that can be installed on a boat, level is meaningless. A skiff can be built on a mountainside as long as it is true to itself. That means, axially athwart framing tops must be parallel. Just like the ways on a lathe, one side cannot be axially lower than the other. Going back to the beginning when this thing was just a bottom, it's a noodle, one can rack and twist it easily; there is NO stiffness to it at all. I've completely welded all the longs and frames and there is little noticeable difference between when it was just tacked in terms of stiffness. BUT THEN things get serious. After the sides are on I chock it up on the dolly at four points, two fore and two aft after sighting across the tops of the athwart frames. The chocks MUST be obdurate. The human eye is a precision instrument and trustworthy. After all, that's what ancient boat builders relied on! When the transom goes on and the bow sewed up it's pretty much over in terms of flexibility. So if you've managed to put a twist in there it's gonna be there forevermore.

I mention 'points of reference'. What do I mean by that? Well, it is that there has to be enough bones, for lack of a better word, in order to flesh out the shape one is attempting. Recall that for all the world the material you are working with has absolutely no desire to be what you want it to be.

A little sidebar here: years ago when all the computer CAD stuff hit where I live there was initially this, "Well, look at these beautiful lines!" but unfortunately, as beautiful as they were they didn't have bones. Thus many of us struggled to make the bones that the material was resisting - we came from the fill in mentality - meaning one joggled athwart frames, longs and decks within a outward computer dictacted shape. It kinda worked but not well. Mind you, I'm pretty sure this was a locale phenomenon. But it sucked. So my point is that there has to be enough points (dictated by longs and frames) that support the idea. Yeah, but how many you say? Ha, ha...ha, ha!

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