Jamie Mantzel's Fiberglass Pontoon/Catamaran Fiberglass Boat Design

Thanks Bajansailor and Mr Efficiency, your feedback is very valuable. I have been able to more thoroughly study Mr. Richard Woods designs and I am very impressed as well, thank you very much for suggesting them! I googled several more sailing catamaran designs that seem pretty good as well, but are Mr. Wood's designs considered the consensus gold standard with the best resale value? Are there other designers that you would recommend as well? Also, although I have experience with fiberglass and epoxy, I don't have experience with foam core (I want to go with the foam sandwich rather than plywood), do they provide step by step instructions to do the foam core if I purchase the plans?

 

mariobrothers88. there is a forum member "fallguy" here, who is well into a build of the Richard Woods power cat, so you may like to look at that. It is a lot of work, and outlay. I understand the desire to keep the costs down, and especially to reduce the amount of hours involved. But you don't want to be getting involved in methods that have a superficial attraction of seeming to circumvent the need for large amounts of time and money, but are unsound in other ways, and especially if compromising safety. And particularly if inviting others to come on trips on a boat that is not "well found".

 

Mario, Richard does design very nice boats that are very well thought out.
I would presume though that he would assume that you already know how to make a foam sandwich panel, if you are intending to build a foam sandwich boat.
Hence it might be a good idea to buy a book or two about this subject?

There are lots of other good catamaran (power and sail) designers - you could also have a look at Derek Kelsall's site
Catamarans - Kelsall Catamarans - Boat Designs http://www.kelsall.com/
Here he explains his KSS method of construction
http://www.kelsall.com/UniqueKSS/WhatIsKSS.pdf

Have a look also at the Schionning designs -
Designs - Sailing & Power Multihulls http://www.schionningdesigns.com.au/designs

 

I have been a Jamie follower for some time. Some things he does as a workaround to eliminate outside sources of material, which apparently are logistically difficult to obtain, let alone transport through the mangroves to his island. Its not that it is the best way to do something. Even going so far to make his own propellers and gear drive system for the pedal version. His other idea to simply use an outboard lower complete with prop and just replace the junk engine with the electric motor, that was a lot better. He seems to be using heavy biaxial roving which is much stronger than CSM but then uses poly resin which is weak and brittle and subject to blistering and of course much less than ideal for any laminating process where you want good interlayer bonds. His pontoons are not well partitioned, I think that a single split on 1 hull will result in that hull sinking and the boat flipping over (assuming the water is deep enough), so he could easily lose everything and I doubt anyone would be coming to rescue him. I have not seen any evidence of a vhf transceiver on him, so I dont know what he does if he has a problem.

Jamie is a very stubborn guy, does not want any advice from anyone. So imitating him is probably not advised....

 

There's nothing wrong with polyester, but ramshackle construction methods are inadvisable in any material, the attraction of short-cut methods is obvious, and whilst rough-as-guts appearance is purely a matter of aesthetics, and no great offence, structurally unsound boats are dangerous, and unconscionable.

 

Cost to build a 45' power or sailing cat is pretty high.

plans cost is incremental, step away from foolishness

 

I recently started a thread about hybrid of stitch&glue and large flat (or flatish) panel fabrication.

Problems addressed were similar. How to get single big pieces to put together. It seems feasible that a single worker could make 30-40' long flatish sections of fiberglass and maybe wood in a simple shed or tent, one at a time, just one easy to work on table and vac-bag setup, maybe transport to final build location, and stitch and glue them together fairly easy with a helper or two to make a chine or multi chine hull. Interior reinforcing stakes, and traverse frame attachment points, of wood and fiberglass to help join the panels could be built into the pre-fab panels.

 

One guy cannot bag a 30-40' section. Sorry. Infusion, yes, wet bag, no way.

 

how about two guys? what is the limiting factor, the working time of the wet?
I'm not a fiberglass guy and only watched wetbag of the very smallest "watercraft", the skim board, but I'm thinking making semi-prefab panels rather than the whole boat would be more forgiving as mentioned by GAC.com below. If you botch one panel chine its not as bad as botching the whole boat. I've done my share of random painting and I really like painting horizontal surfaces if at all possible so I'm thinking same would apply to wetting out fiberglass...the part where the hull starts getting vertical would be the problem areas.


Vacuum Bagging Process vs. Vacuum Infusion Process https://german-advanced-composites.com/vacuum-bagging-process
In larger projects, it is also necessary to apply the vacuum bagging process a couple of times since the resin pot-life is the limiting factor.

• Another imminent disadvantage with hand-lay-up and bagging is that the process must be completed once started, with no option to pause or take a step back.
• There is a clear time and forgiveness disadvantage in wetting-out and squeegee processes with a race against the resin pot-life and getting all of the materials in place.

 

In the context of this discussion, the "method" such as was being demonstrated, more or less dictated the shape of the hull. That is starting off with a constraint that in most cases, you are being limited and compromised by. As Glen Campbell sang, "There's been a load of compromising on the road to my horizon." Whilst compromise is part of life, it isn't a case of "the more the better" in too many things. I can't see a lot of virtue in the "jungle" method.

 

Sorry to burst any bubbles, but one man would fail. Two men are a stretch. Three is best for wet bagging 30-40 foot panels. I have built 9 or 10 panels 33 feet long using wet bagging. With three people our record time was 70 minutes. Our first panel was 110 minutes. We were using a 120 minute epoxy that required post curing.

The Gougeon video is rather odd because there is no way you would succeed wet bagging the way they showed. The bag would get wet edges rendering sealing it impossible. I could go on about that video. For example, you'd never apply the bag after wetting out and you'd never be playing with the vacuum connections that much on hot epoxy. One half of the bag would have already been on a mould flange so you only fold the bag over. Then they don't use a release film which means release can be a nightmare. But they don't show the release! Lots of that video was edited out. All the oh xxxx this sux parts.

 

Also, botching a 30-40 foot panel is better than botching the whole boat, but my panels had a cost of about $1500 each. If you tried as one man and failed; you throw away that.

Here is how the process works.

All resins are pre measured into a&b kits for each pour.

Bag is halfway on. Draped off the work.

Peelply is taped to mould table. A sharpie line defines the glass to come.

Epoxy is mixed and poured and rolled even to edges. 4 minutes

Glass is rolled off a tube onto the wetted substrate. A quick pass with consolidation roller is done for more even coverage. 2 min

Second pour. Wetout. 15 minutes, varies with glass used

For a core build, core epoxy is mixed and the core is wetted on the side going to the bottom or you will get air. 5 minutes to mix, wet, flip into position.

Third batch of epoxy is mixed and part poured onto core. Rolled even. 3 minutes

Second layer of glass is rolled off the tube and a quick consolidation pass 2 minutes

Epoxy is poured on the top. 15 minutes to wetout.

peelply is rolled off and stretched to flat 4 minutes

release film is rolled off 1 minute

breather is rolled off 1 minute

Table drips are wiped clean 1 minute

bag is flipped 1 minute

Gum tape papers are removed and bag is sealed 10 minutes with a few pleats

I accounted for 64 minutes here and the best we ever did was 70. I am sure I was aggressive on the times.

For one man to wetout 66 square feet of triax faster than say 25 minutes, the only way would be to go super heavy on the resin. But one man can't flip a 30-40 foot core section unless it is apart with staple line ups or some such. One guy would really struggle to ever pull off wet bagging a 35' part in under 2 hours. It is stressful with two decent people and a helper.

And this is why infusion is so much better. All the rollout work is done. And the vacuum does the wetting. And there is less likelihood of microvoids and other technical defects.

Noone here ought to ever glorify a jungle hack job of a panel. Jungle methods are not always bad. If you have a problem at sea, creativity is wise. Just forget the idea of building a boat as a hack method. For one thing, all the money you spend would be thrown away because you can almost never sell trash.

 

I'm not TOO hung up "just one guy", could be several, but what about the idea is breaking up the major fiberglass operations into at least 4 but more likely 6 or 8 for multi-chine stitch and glue boat hull. They say bagging is a better product but seems like size of single piece is pretty limited and never heard of anyone doing anything bigger than a canoe. Not sure if fiberglass would like to be bent into permanent new form, but bent fiberglass panels could be made with bend built in on table of flexible 1/8" door-skin plywood. CAD would give measurements off the floor for support sticks. Wood and fiberglass are good together but plywood is very limited in size, so cut parallelograms of plywood to overlap so no butt joints. Hold into the bent mold with sand or water bags. Might be tricky to fit overlaps together nicely and still bend into mold.

 

"old mate" Jamie wasn't concerned about time limitations as much as available space when fabricating his panels, you could pretty easily lay up a long panel on a flat table, using conventional lay-up methods, without any concerns about time, you just keep at it. However, it would need to be pretty uniform, with no thicker areas or overlapping, or it may not bend evenly. I just don't see much application for single skin glass panels.

 

I have 4 lengths of 7metres of matt to lay by hand on my hulls now that the weather has warmed up. To do this I will set up 5 small pots with the correct amount of hardener [epoxy] separate for each to mix up as I go. 3/4 of the way through working each section I will stop briefly and mix the next section. 45 minute working time. I expect to do 2 runs ,one for each hull in a day , some prep and outdoor so 4 hours allowing for 6..at optimum temp.

I have another part of the project that involves bending and screwing thin melamine sheet on to an existing hull ,making a thin fibreglass laminate over, removing melamine then glueing and glassing more layers to the laminate onto hull.
An upside down old proven hull could be copied this way using it as the male form..
Something to consider anyway..it may be of some use to you.