HC14 to Sailing Trimaran!

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fallguy1000
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Re: HC14 to Sailing Trimaran!

Post by fallguy1000 »



My boat build is here -------->

viewtopic.php?f=12&t=62495

narfi
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Re: HC14 to Sailing Trimaran!

Post by narfi »

Ah, solid core or massive core composite. I haven't seen his site, but I am familiar with the method.
One of my favorite sayings,
Soloman wrote: There is nothing new under the sun.
For me, that means that anything I can think up, has already been done, and I just need to find who did it and adapt from there :P

His tutorial page for his massive core outrigger had a maximum width of 6". (he used 3" on each side of his web)
My largest bulkhead is, 17.71" wide by 15.81" high, so significantly more volume, mine wont be training wheels, they will be big enough that a smaller person could probably sail it as a catamaran without the canoe attached in the middle. (over 400lbs of buoyancy per hull)

I am familiar with stitch n glue, so there is no learning curve for me, that directed most of my decision process. I wanted it to be a quick (hopefully) project, not a time to learn new construction methods, even though I am with the mast and beams etc.....

If this was a serious endeavor, or for an aircraft, there are calculations you run at which point the weight advantages for cored composite vs massive core swap based on volume and shape. For a very thin structure, massive core wins out because you only need glass around the outside, so you have a layer of glass on each side of the surface, lets call it top and bottom, for 2 layers. For a thin cored structure the same dimensions, you would need 4 layers of glass(or carbon or kevlar or whatever you are specing...) Glass and epoxy weigh a lot more than wood or foam. So you need to run the numbers to see what your 4 layers of glass/epoxy + 2 layers of core weigh vs your 1 massive core and 2 layers of glass/epoxy.

Because I am using wood not foam it would tip more towards the massive foam core, however as large as my volume is, I am guessing it would still tip in favor of the thin core in terms of weight for the size cross section I am working with.

I find the study fascinating, and wish I had the time to run more numbers on it instead of just theory from memory, but I am already taking time away from other projects to do this, so trying to stay as simple as I can :)

narfi
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Re: HC14 to Sailing Trimaran!

Post by narfi »

Well kind of frustrated with myself......
Started putting the panels together last night. I think they will fit together very nicely, I am happy with that.
However, as you can see in the picture the bulkheads are too big, so I couldn't put the upper side panels on.

The bulkheads are the size I intended, when I modeled it I had each plane 6in apart and the bulkheads drew out perfectly for that. However a simple logic check I didn't do would have saved me this headache..... Each of my panels as drawn and cut out are roughly 6+-in........ If it goes up 6in and over several inches, then obviously it needs to be more than 6in wide....... a²+b²=c² right? I should have seen it and figured it out before cutting......... :(

Luckily even though smaller than I intended, I had been worried I was making them too big..... So it may all be for the best as they seem to fit together nicely.... I just need to figure out what I did wrong and hopefully it is an easy ratio I can shrink the bulkheads to match and it all fits together nicely anyways ........

Fingers crossed :)

You may notice from the picture I made the transoms from scrap 3/8" marine plywood I had instead of the 1/8" I'm doing everything else with, I think it's way overkill buy will give it lots of strength to mount the rudders.
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Jeff
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Re: HC14 to Sailing Trimaran!

Post by Jeff »

Nice work Narfi!!!! Jeff

narfi
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Re: HC14 to Sailing Trimaran!

Post by narfi »

I do think that transom, station 24 and 96 are enough structure after starting last night. So I just recalculated new bulkheads for them based on the actual size of the panels I cut out and keeping original angles/shape.

Will see if it works or not :) as frustrating as screwing something so obvious up, experimenting and learning is kind of fun. And in the end I really just need some floaty things out to the sides of the canoe to keep the wind from tipping it over so it should be just fine no matter how poorly I screw up the math.
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narfi
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Re: HC14 to Sailing Trimaran!

Post by narfi »

Not much time today but cut the bulkheads to my modified calculations and they worked perfectly.

First hull is looking good, need to find some more tape then I'll flip it and start gluing and glass taping the inside.
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narfi
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Re: HC14 to Sailing Trimaran!

Post by narfi »

Got both hulls tapped up. My modified bulkheads worked pretty well but station 96 needed a bit wider at the deck to make the sides fair. Cut the third set from some of the center bulkheads I had decided not to use.

The cool thing about cutting bulkheads/formers for 1/8" panels is that you can make a male and female former with one cut....

Hopefully have enough time to glue and glass the inside seams tomorrow night.
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Jeff
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Re: HC14 to Sailing Trimaran!

Post by Jeff »

Very cool Narfi!!! Jeff

narfi
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Re: HC14 to Sailing Trimaran!

Post by narfi »

I think we made pretty good time last night. 3hrs
Glued and fillited inside seams on both hulls and laid in 6oz 6in tapes which basically glassed the entire inside.
My wife mixed and did the detail work and I applied all the broad strokes.

Went out this morning to check on it and a big fox was watching me.

Not ideal conditions it froze again last night, hopefully the sun bakes the tent this afternoon and they will cure enough to flip tonight and apply filler to all the outside seams in preparation for shaping.
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VT_Jeff
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Re: HC14 to Sailing Trimaran!

Post by VT_Jeff »

Great stuff, Narfi, I'm super impressed with the whole deal!
There are only two seasons in Vermont: boating season, and boat-building season.

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