Foam sandwich option for TW28

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TW28RJ
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Foam sandwich option for TW28

Post by TW28RJ » Thu Sep 27, 2007 3:55 pm

I'm strongly considering building the entire TW28 out of foam sandwhich.

However, before I go down that road, I would like to ask the designer how he would prefer to see his design built?

I understand that the foam core will double the cost of the hull, but that's only a percentage of the whole package. What benefits would I realize building in foam vs. plywood.



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jacquesmm
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Post by jacquesmm » Thu Sep 27, 2007 4:33 pm

Too big a question, sorry. We could write a book about that.
Do a search on this forum and see previous posts about foam sandwich.

Quickly:
Benefits =
- great insulation, a very important point in cruising boats but always overlooked by those have not cruised.
- higher resale value because there is a unjustified prejudice against plywood
- a small gain in hull weight, not much in a 28 footer, means a little bit more capacity.
- hull panels are easier to bend.
Jacques Mertens - Designer
http://bateau.com

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Knottybuoyz
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Post by Knottybuoyz » Thu Sep 27, 2007 4:55 pm

My guestimate was about $3K US more for the hull over plywood. Not quite double the cost, closer to 30% more as long as the fiberglass specs stay the same.

We'll stay with the original plywood version as designed. Reasoning, it's a displacement hull anyways and making it lighter is a moot point unless you need more capacity for equip/cargo/food/beer/fish etc. In all likelyhood you'll be adding ballast anyways.

We may use foam in the deckhouse and cabin roof to reduce topside weight with a small improvement in stability and insulation qualities as suggested.
Yours Aye! Rick
"It's not the boat "you built" until you've sworn at it, bled on it, sweated over it, cried beside it and then threatened to haul the POS outside and burn it!"

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Evan_Gatehouse
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Post by Evan_Gatehouse » Thu Sep 27, 2007 5:08 pm

The fiberglass laminate would increase, not stay the same as the plywood version. So double the cost is accurate.
designer: FB11/GV10,11,13/ HMD18/
SK17,MM21/MT24

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Post by TW28RJ » Fri Sep 28, 2007 9:20 am

Thanks everyone for your reply. I think that I've convinced myself that foam sandwich is the way I should proceed.

The benefits that Jacques mentioned (quoted below) and the sound absorption properties are more than enough to convince me.
-great insulation, a very important point in cruising boats but always overlooked by those have not cruised.
- higher resale value because there is a unjustified prejudice against plywood
- a small gain in hull weight, not much in a 28 footer, means a little bit more capacity.
- hull panels are easier to bend.
I personally have no problem whatsoever with plywood, but let's face it people of that opinion are in the minority. After I have had a chance to review the fiberglass hull scantlings I may reconsider the plywood option.

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Post by Knottybuoyz » Fri Sep 28, 2007 11:36 am

RJ

Send me an e-mail and I'll send you back my MS Excel spreadsheet for the TW28. It's got a lot of links to suppliers etc. that I've found with the best prices. It's a good planning tool for your project.

knottybuoyzii (at) personainternet.com

Rick
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Post by TW28RJ » Tue Oct 02, 2007 9:28 am

Send me an e-mail and I'll send you back my MS Excel spreadsheet for the TW28. It's got a lot of links to suppliers etc. that I've found with the best prices. It's a good planning tool for your project.


Hey Rick, thanks for offering the spreadsheet it would be very helpful at this point in the project. I have in fact emailed you a couple of times, but I'm not sure if I got the address right. So here's mine -(Ron.Johnson@ideas4eng.com)

I received the composite samples I had ordered last week and needless to say I'm very impressed with the divinycell. The foam sandwich is definately the way I want to proceed.

I requested the fiberglass hull scantlings from Jacques and it will be interesting to see what they look like when I get them.

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Post by Knottybuoyz » Tue Oct 02, 2007 11:11 am

Files sent Ron.

Let me know if you get them.

New SPAM filter at home works too well sometimes.

Rick
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Post by TW28RJ » Tue Oct 02, 2007 11:24 am

I got them thanks!

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Post by jacquesmm » Tue Oct 02, 2007 2:36 pm

I wrote the foam sandwich scantlings last year, edited the building notes but we are still printing the old file!

I'll work on it and will send you a copy by email.
Jacques Mertens - Designer
http://bateau.com

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