Steve's PH22

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ProfzrX
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Re: Steve's PH22

Post by ProfzrX »

fallguy1000 wrote: Wed Sep 15, 2021 5:41 pm My inserts were almost too narrow at 1.25", too. Try to avoid skimping.

Some people purposely leave inserts high or low to find them later. I am on the hardtop.

Order enough coosa for the transom and for cleats and i nserts. Benchtops in 1/2-3/4" coosa are wise as is the entire gunwhale.

Used 3/4" marine ply in a benchtop that filled with water here in the yrd and it broke my laminate and messed up my paintjob

Freight is so costly, make sure to get plenty of hd core for inserts, transom, gutters even. I made gutters from aquaplas. There are different weights of hd core. 26# for transom, 20# for benchtops and screwholds, 12# for in hull load inserts or as spec'd by JM.

I had to buy more core along the way fir this build...freight is a bugger. I expect you'll experience some of same. Make sure to use a 25% waste factor. Yes you can buuld up core and use small pueces like I showed, but damnit if a guy misses stuff..



Thank you for the information. Have you used the aquaplas on any other builds? My concern would be screws backing out on places where I cannot use a thru bolt with backer nut. What I like about the pultruded fiberglass is you can tap and die it to hold screws. Ive also been told and have read on other forums that Coosa will not hold screws. I guess the bluewater 26 is said to be able to by the manufacture but some have done tests showing they typically fail.

fallguy1000
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Re: Steve's PH22

Post by fallguy1000 »

ProfzrX wrote: Thu Sep 16, 2021 3:59 pm
fallguy1000 wrote: Wed Sep 15, 2021 5:41 pm My inserts were almost too narrow at 1.25", too. Try to avoid skimping.

Some people purposely leave inserts high or low to find them later. I am on the hardtop.

Order enough coosa for the transom and for cleats and i nserts. Benchtops in 1/2-3/4" coosa are wise as is the entire gunwhale.

Used 3/4" marine ply in a benchtop that filled with water here in the yrd and it broke my laminate and messed up my paintjob

Freight is so costly, make sure to get plenty of hd core for inserts, transom, gutters even. I made gutters from aquaplas. There are different weights of hd core. 26# for transom, 20# for benchtops and screwholds, 12# for in hull load inserts or as spec'd by JM.

I had to buy more core along the way fir this build...freight is a bugger. I expect you'll experience some of same. Make sure to use a 25% waste factor. Yes you can buuld up core and use small pueces like I showed, but damnit if a guy misses stuff..



Thank you for the information. Have you used the aquaplas on any other builds? My concern would be screws backing out on places where I cannot use a thru bolt with backer nut. What I like about the pultruded fiberglass is you can tap and die it to hold screws. Ive also been told and have read on other forums that Coosa will not hold screws. I guess the bluewater 26 is said to be able to by the manufacture but some have done tests showing they typically fail.
What screws is the question..

A screw holding a bus bar isn't going to fail in aquaplas as fast as it will in an M80 or M100 corecell core.

But you won't mount the console with screws; you'd use glass on the inside of the cleat and the console face and you'd bolt with 1/4" and finish washers.

I don't have anything screwed that matters; save for maybe the gas tank fills, but they are also bedded in butyl, so fat chance they ever come out.

I have some bolts planned for yellow loctite as well and green for the helm bolts.

What you need for bolt holding is crush resistance. 3 ways to get it.

1. Hd foam inserts
2. Overbore 2-3x and fill and redrill (all plywood gets overbored to prevent rot)
3. Metal bushing to precisely the thickness/depth of the hole.
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fallguy1000
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Re: Steve's PH22

Post by fallguy1000 »

Further, if the aquaplas allows a screw to turn out (can't see it), I can always glue the bus bar down on four corners.

You have a different game going with a go fast wave jumper, but I'd trust the aquaplas higher or coosa bw to hold a busbar.
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jacquesmm
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Re: Steve's PH22

Post by jacquesmm »

fallguy1000 wrote: Mon Sep 13, 2021 3:57 pm . . . but the problem with the a500 core is the interface between the bottom or top deck and the sides. JM will show the OP what to do, but what happens with an a500 core at the hulls edge is massive compression loading.
I'm back. The remark above is correct and very important. A few days ago, I did email Matt a few drawings explaining how to handle those corners (I call them hinges). The solution is a transition to single skin. I don't want to post the drawings here, I am afraid that they my be copyrighted. I may redraw them my way.

More further down.
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Re: Steve's PH22

Post by jacquesmm »

OneWayTraffic wrote: Mon Sep 13, 2021 10:47 pm

As I understand it yes.

I think the real issue is less the thickness of the core, and more the skin/core interface. At those speeds I'd expect some pretty hefty skins to be specified, which is why part of me wants Steve to build as per standard, and part of me wants to see an extreme build. Either way I will be following this thread.

If there was a pool for guessing the final layup I'd be putting my money on a 3/4" core (at least 100kg/m density) and about 4/3mm of directional glass on the outer skin and inside respectively. I could be way off obviously.
Correct, it is shear failure that worries me. Either in the foam or at the interface. That is why I must specify Corecell 500 for high speed.
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Re: Steve's PH22

Post by jacquesmm »

I was busy on some other projects, some personal but worked on the lamination schedule.
It took me a while to realize that Matt was the DE23 Matt. I would have worked faster.
Anyway, the lamination schedule in the very first post was not far off considering that it was for polyester.
I use less glass but still, the bottom is thicker than some 25' moderate vee boats.

This week-end, I will send Matt my specs for different versions.
I used different types of calculations and for 250 HP (I did set it at 40 knots and 3,500 lbs), I always get a quite thick bottom.
It is mostly because of the deadrise. In his formulas, Dave Gerr does not introduce deadrise as a variable but all others do.
That boat is not going to be lighter than a plywood cored one.
Even with Corecell and careful building, I am still worried about shear failure with 250 HP.

For the Divynicell that Matt bought, let's use it for the stringers, frames, soles and deck. It will not be wasted. The stringers are 2.5" wide now!
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fallguy1000
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Re: Steve's PH22

Post by fallguy1000 »

jacquesmm wrote: Fri Sep 17, 2021 12:08 pm I was busy on some other projects, some personal but worked on the lamination schedule.
It took me a while to realize that Matt was the DE23 Matt. I would have worked faster.
Anyway, the lamination schedule in the very first post was not far off considering that it was for polyester.
I use less glass but still, the bottom is thicker than some 25' moderate vee boats.

This week-end, I will send Matt my specs for different versions.
I used different types of calculations and for 250 HP (I did set it at 40 knots and 3,500 lbs), I always get a quite thick bottom.
It is mostly because of the deadrise. In his formulas, Dave Gerr does not introduce deadrise as a variable but all others do.
That boat is not going to be lighter than a plywood cored one.
Even with Corecell and careful building, I am still worried about shear failure with 250 HP.

For the Divynicell that Matt bought, let's use it for the stringers, frames, soles and deck. It will not be wasted. The stringers are 2.5" wide now!
Pretty sure Steve is the original poster. Matt just contributed to the discussion. Sorry to confuse, but we are all trying to help a bit.

If you are worried about shear failure, then why don't you use a higher shear core Jacques? How does one calculate minimum shear of the skin if I may inquire?

My primary concern, as a builder, is laminate quality.

Steve may end up with a resin rich layup that performs poorly. Or, if he has a void, that will result in delam after paint.

I might have a laminate on my boat that is so dry, a barnacle ends up pulling glass (gulp).

I think the weight may end up only a wee bit less than ply. I'd be concerned even internals and furniture needs to be taped with heavier tapes. Instead of say a 6 oz woven or a 12 oz biax, a 1208 tape or even two or a 1708 or two, for example.

If I have the name wrong, please tell me.
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viewtopic.php?f=12&t=62495

OneWayTraffic
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Re: Steve's PH22

Post by OneWayTraffic »

Would strip planking in core foam, using little I-beams of epoxy putty between the strips help shear failure at all? Strip planking in wood is a common method here down under. The idea is that the epoxy putty fills fairly generous gaps in between the strips and the wood core can be pretty much any low weight wood, as the epoxy is strong enough by itself.

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Re: Steve's PH22

Post by Matt Gent »

Not my project! Way too big a scope for me.

I just come to offer my experience and pithy commentary.

fallguy1000
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Re: Steve's PH22

Post by fallguy1000 »

OneWayTraffic wrote: Fri Sep 17, 2021 4:33 pm Would strip planking in core foam, using little I-beams of epoxy putty between the strips help shear failure at all? Strip planking in wood is a common method here down under. The idea is that the epoxy putty fills fairly generous gaps in between the strips and the wood core can be pretty much any low weight wood, as the epoxy is strong enough by itself.
Well, the problem with the concept is it is done as a shear web to prevent mass failure (when) the core fails. However, a shear web assumes failure, so we don't see it applied as a convention.
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