Books about composite boatuilding

Raz'r

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De Nile
i want my hull be light and able to get me from point a to point b fast, also having a chance of not penetrating the hull by a stray container, its fine if the outer layer will be penetrated, but you know...it would be nice to be able to get to the harbor without ditching a boat.
A wood core, either strip, tortured ply, and a crash bulkhead would work very well. A nice side effect is that the fairing of the hull results in wood shavings and wood dust, not plastic dust. Some commercial builders still use this method (Steve Rander of Schooner Creek Boatworks is one) https://www.schoonercreek.com/custom-boat-building-past-project

The West book on wood-epoxy boatbuilding will tell you everything you need to know about this method.

I made a small catamaran for my kids using this method - strip plank bottom using bead/cove strips ala building a kayak, and ply topsides and deck, coated in glass. It's a Dudley dix design, and he has a few cruising boats using similar methods of construction. https://www.dixdesign.com/designs.htm

Nice thing about using a design of his is you can have a local mill CNC out your jig frames.
 

Zonker

Super Anarchist
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Canada
Wood core boats suffer from low resale value. So I wouldn't build one (though I like wood/epoxy boats)

I also wouldn't use BV rules. I hate BV rules. Tons of "look here for this factor and then go back 3 pages for this one. Now that you have factor m,n they both = 1 anyway." Then the rule sneers at you with a French accent.

I would use ABS Offshore Racing Yacht rules. While somewhat obsolete they were simple to use and good enough for a amateur build.
 

giegs

Anarchist
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Arid
Wood core boats suffer from low resale value. So I wouldn't build one (though I like wood/epoxy boats)
Is that equally true for ply and strip? I'd expect ply to be hit harder due to how water can travel through the larger sheets used.
 

pironiero

Anarchist
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I made a small catamaran for my kids using this method - strip plank bottom using bead/cove strips ala building a kayak, and ply topsides and deck, coated in glass. It's a Dudley dix design, and he has a few cruising boats using similar methods of construction.
nah man, classic styled cruiser do not get my rocks off at all, i want my boat to look like a ufo or spaceship and IMO Lift 40 v2 looks just like that
 

Zonker

Super Anarchist
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Canada
Is that equally true for ply and strip? I'd expect ply to be hit harder due to how water can travel through the larger sheets used.
Ply - even lower resale value. I base this on the asking price of larger wood core boats I've seen for sale. Usually I say "wow that's a deal" - and then read it has a wood core and I figure out why.
 

longy

Overlord of Anarchy
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San Diego
I'm a lazy typer p/p = prepreg
I'm trying to learn here, not argue. No one's contesting the expense of prepreg fabrics - but do note they are epoxy resins and carbon cloth (to the best of my knowledge, never heard of p/p in a e or s cloth)
So, as you're vacuum infusing, how do you control ratio? How do you measure ratio inside bag?
 

Raz'r

Super Anarchist
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De Nile
is more labor intensive i guess?
Hmm, I don't know - we're talking about a one-off here, which usually means a male mold. To build a solid male mold you're likely going to strip plank that anyway. And fair it. And glass it and seal it. and then put your cloth-foam-cloth over that. It probably is easier to fair the outside of the mold, and get the inside of the boat perfect, and then fair the outside of the foam - than it would be to fair the inside of a strip planked hull. It's all measured in the hundreds of hours anyway (for the fairing)
 

harryproa

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So, as you're vacuum infusing, how do you control ratio? How do you measure ratio inside bag?
It is automatic. It is also consistent and the least possible resin for the reinforcement, assuming everything is set up properly which is much easier with a flat panel than a curved one.
To infuse, all the air is removed from the laminate, along with any moisture if it is left long enough. The minimum amount of resin to fill the void inside the bag is sucked in. No more and no less. Everything is prepared dry, then the resin allowed in. Low stress.

With wet laminating and bagging, the excess resin and air has to be sucked from the laminate and any leaks found before the resin cures. High stress.

The prepreg (carbon, kevlar or glass) story is different. The layers of preimpregnated, partially cured laminate are laid in the mould. Between the layers, air is trapped. Every couple of layers it is warmed and debulked, removing most of this air. When the laminate is complete, it is bagged and heated sufficiently to cause the resin to flow. Any air still in the laminate should flow out at this stage. Any excess resin (prepregs are wet with a stated percentage of resin, which is usually a little more than optimal) is also squeezed out.

An autoclave applies more pressure, possibly removing more excess resin. But no matter how much pressure is applied, it is impossible to exceed the space available for resin when the air is evacuated under the vacuum of infusion.

The reason some laminates are marginally lighter when prepregged and/or autoclaved is because the prepreg is held together with part cured resin, the dry infused laminate requires stitching. The stitching adds a small amount of weight and more interstices to be filled with resin.

Pironeiro,
It is hard to think of a boat more different to a Harryproa than a scow bowed 40! My bad for not reading your post. It is also hard to think of a more difficult shape to build in foam and glass. You have several options:
The best result will be from a female mould, for which you will need a plug. You end up building 3 hulls. Next best will be a male mould. You end up building 2 hulls. All have to be fair and shiny to allow a release. Both methods involve bagging the outer skin, the core and the inner skin in different steps. You need to really enjoy boatbuilding to use either of these methods.
Easiest is to strip plank it using foam with unidirectional and peel ply on one (more frames required) or both sides, then seal the exposed skin (male frames are easier to fair and bag, female allows the internals to be completed before turning the hull) and either wet laminate or infuse it. Infusion requires a good plan for the resin path, something which gets easier each time, but can be difficult the first time.
Terminating the strips at and around the bow will be an interesting challenge. Allow plenty of extra for fairing this area. I look forward to seeing how it all comes together. I'm happy to answer questions if you have any.
 

Zonker

Super Anarchist
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Canada
I would probably do it Ian Farrier's newer way with vertical strips.


Lots fewer strip joints. I think with the larger curvature of the monohull you still have to longboard the foam on the outside a bit after the inside skin is on, but shouldn't take too long
 

slug zitski

Super Anarchist
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worldwide
It is automatic. It is also consistent and the least possible resin for the reinforcement, assuming everything is set up properly which is much easier with a flat panel than a curved one.
To infuse, all the air is removed from the laminate, along with any moisture if it is left long enough. The minimum amount of resin to fill the void inside the bag is sucked in. No more and no less. Everything is prepared dry, then the resin allowed in. Low stress.

With wet laminating and bagging, the excess resin and air has to be sucked from the laminate and any leaks found before the resin cures. High stress.

The prepreg (carbon, kevlar or glass) story is different. The layers of preimpregnated, partially cured laminate are laid in the mould. Between the layers, air is trapped. Every couple of layers it is warmed and debulked, removing most of this air. When the laminate is complete, it is bagged and heated sufficiently to cause the resin to flow. Any air still in the laminate should flow out at this stage. Any excess resin (prepregs are wet with a stated percentage of resin, which is usually a little more than optimal) is also squeezed out.

An autoclave applies more pressure, possibly removing more excess resin. But no matter how much pressure is applied, it is impossible to exceed the space available for resin when the air is evacuated under the vacuum of infusion.

The reason some laminates are marginally lighter when prepregged and/or autoclaved is because the prepreg is held together with part cured resin, the dry infused laminate requires stitching. The stitching adds a small amount of weight and more interstices to be filled with resin.

Pironeiro,
It is hard to think of a boat more different to a Harryproa than a scow bowed 40! My bad for not reading your post. It is also hard to think of a more difficult shape to build in foam and glass. You have several options:
The best result will be from a female mould, for which you will need a plug. You end up building 3 hulls. Next best will be a male mould. You end up building 2 hulls. All have to be fair and shiny to allow a release. Both methods involve bagging the outer skin, the core and the inner skin in different steps. You need to really enjoy boatbuilding to use either of these methods.
Easiest is to strip plank it using foam with unidirectional and peel ply on one (more frames required) or both sides, then seal the exposed skin (male frames are easier to fair and bag, female allows the internals to be completed before turning the hull) and either wet laminate or infuse it. Infusion requires a good plan for the resin path, something which gets easier each time, but can be difficult the first time.
Terminating the strips at and around the bow will be an interesting challenge. Allow plenty of extra for fairing this area. I look forward to seeing how it all comes together. I'm happy to answer questions if you have any.
Yah

difficult shape to build …imagine how many man houts to build one of the steel fin, lead bulb keels

better to choose something simple , with a simple, non technical non overstressed keel

something like a pogo 12.5

7152935E-ADC8-43E7-B0B4-584013C0C4D8.jpeg
 

longy

Overlord of Anarchy
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1,283
San Diego
OK, E-glass is available, epoxy resin, resin content 30% +/- 3%. Their carbon twill is 37% resin
ProSet resin:

Vacuum Bag Laminating​


Vacuum bagging is an excellent clamping method for composite construction using PRO-SET Laminating Epoxies. Regulating the amount of vacuum pressure permits control of the resin/fiber ratio and can produce a more dense laminate, with a higher fiber volume. Generally, the higher the vacuum pressure, the lower the resin content. The optimum resin/fiber ratio for a particular component will be between 30% and 50%. A lower ratio will result in a lighter composite. A higher ratio will be heavier, yet yield higher moisture exclusion effectiveness. Various bleeder and absorber materials used in vacuum bag laminating can also influence the resin/fiber ratio. Building test panels is recommended to determine the proper vacuum bagging material schedule and vacuum pressure for a particular component.

file:///C:/Users/trish/Downloads/guide-to-composites.pdf

The reason some laminates are marginally lighter when prepregged and/or autoclaved is because the prepreg is held together with part cured resin, the dry infused laminate requires stitching. The stitching adds a small amount of weight and more interstices to be filled with resin.
Reading several articles on infusing recommending stitched fabrics for better flow during infusion.
Minimum resin content seems to be 30%, and can be achieved with p/p & standard (1 atmo) vacuum bagging
 

Black Jack

Super Anarchist
Cold molded boats are still the best if they are one offs. More sustainable and less Eco damage and much likely cheaper. Done right - they are as nearly the same weight as an modern vacuum method with less sophisticated tooling. The boat will also have a more secure feel under way.


Maybe one of the best free books out there.
 
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Because in some cases you can get better fiber/resin ratios at less cost than prepreg. This is for something like a surf ski or racing kayak. Again, I’m not suggesting this, merely pointing out some nuance when comes to infusion and composites in general.
(Quote)
With wet laminating and bagging, the excess resin and air has to be sucked from the laminate and any leaks found before the resin cures. High stress. (Quote)

The first quote is correct, the second quote is not! I've been doin composite projects since I was 14.
There is no stress with bagging a wet layup if you know what you're doing! A wet layup allows for engineering layup schedules for extra strength areas when needed and keeping non structural areas as thin and light as possible. There is no bike inside, no metal connecting the wheels because the Kevlar/carbon skin/body doesn't need it. It's also front wheel drive with 48 gears.
The Coyote was a wet layup/bagged project. The carbon, foam cored, Kevlar and titanium streamliner weighs 40lbs, has 60,000 road miles on her, is 35 years old with many bike racing wins and was a World Champion in 1996.

dog2.jpg
 
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Russell Brown

Super Anarchist
1,760
1,441
Port Townsend WA
Cold molded boats are still the best if they are one offs. More sustainable and less Eco damage and much likely cheaper. Done right - they are as nearly the same weight as an modern vacuum method with less sophisticated tooling. The boat will also have a more secure feel under way.


Maybe one of the best free books out there.
Strip planked cedar with glass on both sides turns out to be very light. The hull is easy to fair before glassing and uses less epoxy. Far less filled epoxy to make fair. Cedar is expensive now, but there are alternatives.
 

harryproa

Anarchist
924
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OK, E-glass is available, epoxy resin, resin content 30% +/- 3%. Their carbon twill is 37% resin
Twill has more resin in it as the weave is not flat and because it is a surface layer and pinholing/resin starvation means more finishing work.
The optimum resin/fiber ratio for a particular component will be between 30% and 50%. A lower ratio will result in a lighter composite. A higher ratio will be heavier, yet yield higher moisture exclusion effectiveness.
This effectively only applies to wood and balsa. And even then is not really correct. Vacuum infused timber is rot proof (and heavy).
Building test panels is recommended to determine the proper vacuum bagging material schedule and vacuum pressure for a particular component.
Absolutely.
Reading several articles on infusing recommending stitched fabrics for better flow during infusion.
For sure, but the more you do, the more confident and skilled you get and the less important it becomes. We have infused 20mm thick carbon tow (filaments, with nothing holding them together) without doing anything special
Minimum resin content seems to be 30%, and can be achieved with p/p & standard (1 atmo) vacuum bagging
We regularly get this (70/30) with infusion and unis, more like 67/33 (2:1) with stitched. The difference is small. The cost, time and hassle difference is huge.

Strip planking is definitely easier than cold moulding, especially with scow bows which would be a lot of work and waste to spile the veneers. Strip is also easier than building a plug and mould, or just a plug for a foam boat. But it will not be lighter. From the 'are they full of shit thread?':

Suitable base laminates for a performance 40'ter:

20mm cedar with 600 glass each side
20mm foam with 900 triax each side

Assuming the cedar is hand laid, the resin will weigh as much as the glass.
Assuming the foam is bagged or infused the resin will be half the weight of the cloth, plus 200g each side to wet the foam.

20mm cedar (sg 0.35) weighs 7 kgs per sq m, plus 2.4 kgs of glass and resin: 9.4 kgs/sqm
Bagged/infused 20mm foam (sg 0.08) weighs 1.6 kgs per sq m, plus 3.1 kgs of glass and resin: 4.7 kgs/ sq m.
Hand laid 20mm foam (sg 0.08) weighs 1.6 kgs per sq m, plus 3.1 kgs of glass and resin: 5.6 kgs per sq m

The moulded boats will probably weigh a little more due to the bedding compound needed for the core, but roughly speaking, the hand laid cedar hull will weigh double the infused foam strip one.

If the foam strips are only glassed on the inside, fairing the outside will be easier than fairing cedar. Both will be a pain in the arse around the bow.
 

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