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My newest project

34251 Views 238 Replies 49 Participants Last post by bobperry, May 18, 2015

bobperry

Discussion Starter · Feb 13, 2015

This is a new 43'er for a PNW client. The boat has twin diesels on sail drives. The builder is James Betts in Anacortes, WA. This is a custom project and what you see is what the client wants. But this image is a bit obsolete now. The hull ports have gone. The dink is off the housetop and the cabin trunk portlights are now all the same size. Details. Construction will be composite with epoxy.

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bobperry

Discussion Starter · #21 · Feb 14, 2015

Nauticat:
You are reading it wrong. No conflict at all. I think what you may be reading is my effort to make those not acquainted with custom design understand why this or any other custom design appears the way it does. I based my book on this theme. My work is a reflection of client requirements as filtered through my creativity. As I went to bed last night it occurred to me that my post was quite a rant. I did not start out intending it to be but I was tired an maybe some frustration came through. Sorry.

Thanks for the welcome back. Nice to be back.

Jeff_H

· #22 · Feb 14, 2015

bobperry said:
CC:
I'd rather JeffH answer your question. He knows his stuff and I can;t type worth a damn.
If Jeff doesn't answer it I'll do it.

Bob- Thank you for the vote of confidence.

I think that SloopJonB did a great job of explaining the terms that CCRiders was asking about. In basic engineering terms a composite is simply using dissimilar materials to create a unified structure that takes advantage of the characteristics of each material. As noted the term has been used in many ways in boat building such as wooden boats with metal frames in the late 19th & early 20th centuries, or FG or FG with metal framing.

In the case of an FRP laminate, as a composite material, the fabric/fibers handles all of the tensile loads, and the resin glues the fabric together, takes sheer between the layers and takes the vast majority of compressive loads.

I am not sure that it was clear from the write up that epoxy is a much more expensive resin than conventional polyester or vinylester resin and offers no real strength advantage when used with conventional E or S glass. High strength, low stretch fibers like carbon or Kevlar, require either epoxy or vinylester resin to fully utilize the strength advantages of these materials.

Epoxy does offer the advantage of near zero moisture permeability, which is especially important with carbon fiber which can be damaged by moisture intrusion due to electrolysis or corrosion. Then again vinylester offers similar though not as good strength and permeability characteristics at a less expensive cost, and offers a little better ductility.

Epoxy-Kevlar laminates have particularly higher resistance to abrasion than most laminates and a very good resistance to being punctured in an impact. Vinylester/Kevlar laminates also have very high impact resistance and are used to create bullet resistant military helmets. Vinylester/conventional glass are used for motorcycle helmets. Cored vinylester resin laminates offer the highest impact resistance and stiffness for the fiber involved also offering the added advantage of some sound and thermal insulation value.

Properly laminated the reduced flexure and fatigue of a cored hull offers the longest durable strength characteristics but the layup needs to be perfect. The poor layup and protection of the core on many early cored hulls have given them a bad rep.

Jeff

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bobperry

Discussion Starter · #23 · Feb 14, 2015

Thanks Jon and Jeff.
The only thing I would add is that carbon fiber does not play well with others. You can't just reinforce a polyester/E glass laminate with carbon fiber for extra strength. Carbon does not "load share". In a situation where carbon was combined with E or S glass the carbon would take the entire load before the E or S glass ever saw any load at all.

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MedSailor

· #24 · Feb 14, 2015

Great writeup Jeff on the pros and cons of various laminates. Care to discuss the pros and cons of steel?

Bwuhahaha!

sully75

· #25 · Feb 14, 2015

Love the look Bob. I still don't get the carbon thing at all. Seems like it will be much more difficult to repair, with worse results. For zero benefit. I could see if it made the same boat, but for a displacement boat wouldn't the money be better spent on more glass, more resin?

I get the client part. But since we are talking. Doesn't carbon in this picture make a worse boat?

bobperry

Discussion Starter · #26 · Feb 14, 2015

Sully:
Define "worse" for me please.

T37Chef

· #27 · Feb 14, 2015

I'll take one please ;-)

ccriders

· #28 · Feb 14, 2015

Thanks for the tutorials. I understand more about composite construction than my post would imply, but asked anyway as I inferred from "carbon all around" and the follow on comments that people were talking about different things. I guess one could just substitute carbon fabric for glass fabric, but why would you for the hull of a boat? It seems to me that if you wished for something more better than GRP you would actually be talking as much about the structure of the laminate as you would the materials in the laminate.
It also seems to me that the really big cost increases would be in the manufacturing processes used to optimize the materials so that all those factors like stiffness, compression, abrasion, weight, tensile strength, etc are made more better than GRP.
And that is why I asked the question from the yacht building focus. The demands on the designer/engineer would be considerable to just go "carbon all around", easier said than done. But wouldn't it be really cool to have a boat of this design done up full tilt state of the art composite?
Thanks
John

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bobperry

Discussion Starter · #29 · Feb 14, 2015

This is my design ICON, all carbon hull and an all carbon deck, built 15 years ago and still going very strong.

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smackdaddy

· #30 · Feb 14, 2015

Freakin' cool.

If built in CF, will it be the first-ever CF full-keeler? That will be a very, very interesting study in performance!

bobperry

Discussion Starter · #31 · Feb 14, 2015

Smackers:
I think you are right. But the jury is still out on the material. S glass and epoxy might be a better way to go for durability and cost. Still, the client has this Jones for carbon and he is the boss. I'm waiting for him to show up at the shack now. We'll no doubt discuss this again. If he's happy with the layout I'll post it next week and give you guys a look at a real sea boat layout. He's already happy with the layout he's seen but I've moved on several revisions since he had his last look. I don't let him see the drawings until he's in my office. I need to make my full on dog and pony show presentation.

sully75

· #32 · Feb 15, 2015

Bob: worse for me would be more difficult to modify, harder to repair with potentially worse result, much more expensive with little or no performance gain. That said I'm not a designer, customer or expert on carbon fiber. My understanding is that it's difficult to modify and repair.

smackdaddy

· #33 · Feb 15, 2015

sully75 said:
Bob: worse for me would be more difficult to modify, harder to repair with potentially worse result, much more expensive with little or no performance gain. That said I'm not a designer, customer or expert on carbon fiber. My understanding is that it's difficult to modify and repair.

Dude - why would you want to modify it? It's a Bob Perry design.

And why will you need to repair it? Do you hit stuff?

sully75

· #34 · Feb 15, 2015

I actually have hit stuff. Yep. Still learning. Also I've seen other boats hit stuff and come off their moorings and get rammed and all kinds of stuff. I think pondering the future life of a cruising boat seems reasonable, no? Looks like an amazing boat, obviously. I just don't get the point of the carbon fiber. Free country.

smackdaddy

· #35 · Feb 15, 2015

sully75 said:
I actually have hit stuff. Yep. Still learning. Also I've seen other boats hit stuff and come off their moorings and get rammed and all kinds of stuff. I think pondering the future life of a cruising boat seems reasonable, no? Looks like an amazing boat, obviously. I just don't get the point of the carbon fiber. Free country.

It's really light. It's really strong. It's what the highest performing boats on the planet use. And it can be repaired...even when you run it up on a reef at 19 knots. Ask Nico.

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sully75

· #36 · Feb 15, 2015

When I hit stuff though, I was able to jam some glass and some 610 epoxy in the crack for a half assed repair job at anchor and it held tight for another 6 weeks to windward.

smackdaddy

· #37 · Feb 15, 2015

Then I think you're more concerned with boat repair than sailing. Different strokes.

sully75

· #38 · Feb 15, 2015

Right but really light really strong material in a heavy boat doesn't seem to have much advantage.

smackdaddy

· #39 · Feb 15, 2015

sully75 said:
Right but really light really strong material in a heavy boat doesn't seem to have much advantage.

Then you're obviously missing the point. Later.

sully75

· #40 · Feb 15, 2015

smackdaddy said:
Then I think you're more concerned with boat repair than sailing. Different strokes.

Wait I thought boat repair was sailing? As I understood the design it's for a tough blue water cruiser. To me that implies being self sufficient in repair work. Anyway. I'm not the buyer. My boat is probably not worth the price of three winches on that boat. Just an observation.

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