Fiberglass Laminations for Strength and Fairing

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hwsiii
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Post by hwsiii »

Thank you Tom. I didn't include that I also intended to use the biax as a filler between the tape joints at the keel and the chines as a way to help fair these areas up to the height of the tape joints. I made an error in not stating that as part of my intentions in my post as I forgot to include it, but I did state that in the Topic Heading. I do not like to ruffle anyone's feathers, especially Jacques, as I do believe he designs a premium product or I wouldn't be here. I am not always good with my wording or trying to transfer my complete thoughts into words online. I do not take enough time to "ponder" how my statements can be construed as Larry says. When I have an idea that seems reasonable I ask, that way I get other peoples recommendations and/or reasons not to do it. In the long run it helps me to make the correct analysis and judgement call of what I should do. This drawing shows my thought pattern on this and it made sense to me at the time. LOL



Image


HWS



steve292
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Post by steve292 »

Filling between the tape joints with glass is a valid technique, indeed the Cracker did it on his OD18 bottom. I would think that it is heavier than fairing compound,but will help with the fairing process.At the end of the day, I think it would be up to you as to wether it is a trade off worth having.
Just my 0.002.
Steve

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Cracker Larry
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Post by Cracker Larry »

Yes, I did the same thing for the same reason on my OD18 using 12oz. biax. I don't know if it's any heavier than a lot of fairing compound, but I'm sure it's stronger, and gives another abrasion layer against the rocks and oysters.

Nothing wrong with you question or idea HWS 8) Jacques lamination schedule provides more than enough strength, but if you anticipate heavy and hard use a little extra protection is not out of line. It will add weight and cost, an OK trade off for me and my intended use.
I do not like to ruffle anyone's feathers, especially Jacques,
He's just joking with you. You aren't ruffling feathers 8)

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Post by jacquesmm »

hwsiii, do you have the plans and did you look at the lamination schedule?
There is already a lot of fiberglass there and with the overlaps that we specify, you will have extremely strong chines, keel and transom seams.
As Joel wrote, we get the 0-90 fiber orientation from the plywood and add the 45/45 to create an isotropic material.

I know that many builders add a layer or two. That is not a major problem.
What upset me were the words "to use in rough waters and for maximum rigidity". That boat is designed for use in rough waters and all our boats are incredibly rigid thanks to the monocoque structure.
Contrary to production boats, in our boats all parts including frames, sole and deck participate in the structure to create a very stiff and strong beam.
In a production boat, the deck and sole are tied to the liner and do almost nothing except looking pretty.

You, like most of our builders, will be surprised by the strength and stiffness of our hulls.
If you feel better with one or two more layers, please do it. As long as you do not excessively increase the weight, it's not a problem.
You will feel better about your boat and we may sell more fiberglass.
:P

PS: no bad feelings here. Sorry for the outburst.
Jacques Mertens - Designer
http://boatbuildercentral.com

TomW
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Post by TomW »

I plan on doing exactly the same thing do to the shifting sand bars and floating logs on the Mississippi. I want the extra protection. So there are reasons for doing what you propose.

I am also using Meranti on the bottom panals since there is very little bending in the C17 and it is stiffer than Okume. And all Meranti inside.

Tom

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Post by Spokaloo »

I clobbered a deadhead last year that, once we went back to look at it, weighed probably 50+lbs. Hit just left of the centerline of the boat at over 25mph by gps. Unintentional, and a helluva shot to the hull.

I have to say I was disappointed in the durability....



Of the paint....

Not even so much as a dip or crack in the glass, smooth as a baby's butt and just needed paint touchup.

E

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Cracker Larry
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Post by Cracker Larry »

Yep. I hit a submerged oyster rake in my GF16 running wide open, 30 mph. Picture a pile of rocks with razor sharp edges. It sounded terrible and I thought it may have ripped the bottom out. It would have on a fiberglass production boat. But surprisingly no leaks developed and we finished out the day.

I was scared to look at it when I pulled it out, knowing the glass was destroyed. But no, I was amazed to find zero damage except to the paint. The glass was not even scratched. Not a chip. That was 2 layers of 12 oz. biax. It made a believer out of me 8)

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hwsiii
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Post by hwsiii »

It was my fault for not choosing my words better Jacques. I have not purchased the plans yet, so I have no idea what the lamination schedule you designed is. I was theorizing on the concept I was thinking about. I am sure it will help in fairing the boat and add more strength than the quickfair, but I was sure I had not considered all of the variables involved, and one of the parts I hadn’t thought through Joel mentioned, the plywood is already at 0/90 degrees. I have been to many other sites and looked at their designs, but I did not feel as comfortable as I do here, and you actually include things like the study plans and designed speeds with the required horsepower (free) to help us make a better informed decision in the end as to what boat better fits our intended uses. So if you would please take my posts as the rambling thoughts of a man who is just trying to get up to speed on the new techniques (to me) in boat building. If I had to build something like the PG25 the old way, I would not even give it a thought, I just would be buying something in the production models. Although the way the market has been for a while, I can’t stand anymore, or I won’t even be able to build what I want. I am a research oriented individual and have to know how and why things work and don’t work.
Knowledge is something you can never have enough of, I only wish I had the wisdom to go with it.

HWS
Last edited by hwsiii on Sun Feb 01, 2009 1:46 pm, edited 1 time in total.

Daddy
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Post by Daddy »

HWS I can only speak for myself but ask all the questions you want and don't be hesitant to speak your mind, as you can see, we do.
Questions are the only way to learn, and you would be surprised to know, you are not the only one to learn from your questions. Some folks are too timid to ask but are probably glad that you did. As you can see, 18 have responded but over 400 have read the thread.
Glad you are with us, hope you enjoy your build.
Daddy

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Post by Dave Raftery »

I am thinking about building a 15 foot, stitch and glue sailboat with a 3 1/2 foot beam (Enigma 460). The plans call for 2 layers of 9 oz tight weave fiberglass cloth for the bottom, inside and out. I was thinking of using 2 layers of 12 oz biax (45/45) glass fabric instead, which I see is sold by Bateau. Will this give me a stronger boat? I understand that less resin is needed when using biax, so the boat should be lighter as well?
What do you guys think?
Thanks,
Dave

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