catamarans manufacturing process(es) info

[c-reel]

I’m looking for information on catamarans manufacturing steps and processes, especially when comparing different builders.
How they do it and the pros and cons of their approaches.

Not sure if there are some good links, articles or videos, explaining the different steps that anyone can point to.

For example, it looks like for some builders, (especially lower volumes - let’s say Catana, Outremer, possibly Nautitech and not sure about older Robertson&Caine), after the hull and deck are "put together", the architecture of the boat if “enforced” by all the bulkhead, partition walls, etc., which have a major impact on the boat’s structure (some would say enhanced structural strength, while i'm not sure this is correct way) .
With Lagoon or FP, and again maybe with new Leopards which look quite open in the inside hulls/cabins, the boat structure enforcement has to be done differently (as you don't see as much apparent bulkhead in the hulls), and not sure how exactly.

Depending on the construction approaches, would some be more robust over time ? Or is this more driven by manufacturing constraints ?

Sorry if this is an obvious aspect of Catamaran construction. I'm just curious to understand this a bit.

[Cotemar]

1) Build 1 piece or 3 piece hull.
2) Install frame and structure.
3) Install Wiring
4) Install Plumbing
5) Install Engines
6) Put a bead of glue all the way around hull joint.
7) Lower top of boat onto bottom of boat.
8) Screw together hull joint.
9) Install all finishings

[smj]

You usually get what you pay for.

[Factor]

Originally Posted by Cotemar

1) Build 1 piece or 3 piece hull.
2) Install frame and structure.
3) Install Wiring
4) Install Plumbing
5) Install Engines
6) Put a bead of glue all the way around hull joint.
7) Lower top of boat onto bottom of boat.
8) Screw together hull joint.
9) Install all finishings

That is certainly one way.

[Factor]

As well as methodology you would be well advised to focus on 3 important things, Core/Cloth/Resin

eg a balsa core with chopped strand mat or eglass and polyester resin would last a very short time compared to foam with carbon/kevlar/s glass and epoxy or vinylester resin

Process control is also important, eg is it laid up in a vacuum infusion process in controlled or at least monitored conditions? Or thrown at a plywood mould while its raining.

[iliohale]

Read my notes from my factory tours of FP and Nautitech last fall:

http://www.cruisersforum.com/forums/...ch-172776.html

[c-reel]

Originally Posted by iliohale

Read my notes from my factory tours of FP and Nautitech last fall:

http://www.cruisersforum.com/forums/...ch-172776.html

Thank you Gary,
this is very useful indeed. I also read your other notes when trying the N46, showing that manufacturing impression is just one part of the story.


What I'm very curious about is the "step2" from Cotemar above, even more than the type of material. If (as) the bulkhead have a key contribution to the overall structure of the cat, there has to be ways for Lagoon and FP (and others) to make sure their latest cat are also strong there.

Regarding the "you get what you pay for" comment, i think i get that if you have to assemble the boat entirely before building all the inside wood structures and bulkhead, it is going to be more expensive (compared to what it seems Lagoon and FP are doing, while again this is what i try to picture better). Still it won't explain entirely why one type of boat would be more robust than another - or if so overtime/use or over stress of high seas.

Sorry, i know I'm confused, but thanks for the above explanations.

[Cotemar]

Originally Posted by c-reel

What I'm very curious about is the "step2" from Cotemar above, even more than the type of material. If (as) the bulkhead have a key contribution to the overall structure of the cat, there has to be ways for Lagoon and FP (and others) to make sure their latest cat are also strong there.

Maybe these pictures of a catamaran being built will help.
.
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[c-reel]

Originally Posted by Cotemar

Maybe these pictures of a catamaran being built will help.
.
.

Yes, it does. Thanks!
Anyone has pictures of the Outremer and Catana processes, because i believe (but could be entirely wrong) that they are different.

[Cotemar]

Originally Posted by c-reel

Yes, it does. Thanks!
Anyone has pictures of the Outremer and Catana processes, because i believe (but could be entirely wrong) that they are different.

Outremer and Catana build processes are so much different.

They use a 3 part hull.
They take so much longer to build.
They build much less of them.
The list goes on and on.

https://www.youtube.com/watch?v=FBtJr80RIm8

.
.
.
.

[valhalla360]

A lot depends on the intent.

Balsa and chopped strand can produce a very strong very long lived boat but likely not a high performance boat (of course there are exceptions to that).

A foam cored carbon fiber boat will typically be a high performance boat (or at least marketed as such) but if it's not built to very high standards, it could be weak and short lived (and if they don't do it right, it may not even be very high performance).

Build methods: Any of the them work well if done well and any work poorly if done poorly.

So what are you looking for in terms of a cruising boat?

[iliohale]

Originally Posted by c-reel

Thank you Gary,
this is very useful indeed. I also read your other notes when trying the N46, showing that manufacturing impression is just one part of the story.


What I'm very curious about is the "step2" from Cotemar above, even more than the type of material. If (as) the bulkhead have a key contribution to the overall structure of the cat, there has to be ways for Lagoon and FP (and others) to make sure their latest cat are also strong there.

Regarding the "you get what you pay for" comment, i think i get that if you have to assemble the boat entirely before building all the inside wood structures and bulkhead, it is going to be more expensive (compared to what it seems Lagoon and FP are doing, while again this is what i try to picture better). Still it won't explain entirely why one type of boat would be more robust than another - or if so overtime/use or over stress of high seas.

Sorry, i know I'm confused, but thanks for the above explanations.

In my opinion, and I am no expert here by any means, I think the following principles apply:

1. All catamarans as a structure are going to work somewhat, the forces are just to too great across the form factor of a catamaran. You could way over build the boat to keep it rigid but at a high price in terms of $ and weight.
2. Rigidity of the structure is going to be based on the specific design of the boat, layup specs, material specs, and then the actual construction execution such as bonding of the bulkheads and the layup and resin infusion process.
3. In design all of these factors should be taken into consideration with the goal of producing a boat that is safe and long lived at the lowest possible price in terms of materials and labor. It is OK not to fully bond the bulkheads for example as long as the designer has allowed for this in the design and structural analysis.
4. I think there are a few key criteria that a prospective buyer can evaluate to determine if a boat will be safe and long lasting. a.) What safety factors are designed into the build specifications; b.) how experienced is the designer, what his his/her track record; and c.) How well is the builder executing against the design specification.

Getting this information will be difficult for a non-custom boat. So this leaves you with looking at owner feedback and the history of the boats produced by the manufacturer. For established manufactures like Lagoon, Leopard, FP, Outremer and so on, there are plenty of owners that have provided feedback on the quality and longevity of their boats. For smaller and newer manufacturers there is less available information, so be cautious. For those situations I don't think it unreasonable to ask about the design safety factors, experience of the designer, and then to perform build surveys to ensure that the boat is meeting the expectations of the designer from a quality of material and construction standpoint.

These are the principles that I am applying as I shop for my own boat. The best feedback I have received so far has all come from current owners and actual sailing experience on the specific boats I am evaluating.

[c-reel]

Originally Posted by Cotemar

Outremer and Catana build processes are so much different.

They use a 3 part hull.
They take so much longer to build.
They build much less of them.
The list goes on and on.

.
.

Thanks again, how did i miss this timelapse?!


So as the catana and Outremer build process are so much different, there are several outcomes: the boats are lighter, and when properly loaded typically faster. They tend to point much better, etc... and cost cost to 50% more.

But would their structure survive a storm beating better, or would they last for much longer. It's often the perception, but wasn't clear from construction point of view.

To valhalla360,
it is not so much about the boat I'm looking for, but more about the program (where, when) and project (how long) to adapt. I've heard people claim only catana or Outremer can sail the Indian Ocean... But then:

https://www.youtube.com/watch?v=hQ-svmgOxqw&t=1s

(boat is important, crew as well!)
And many under-equipped chartered-type Lagoons or FPs take beating successfully going through the Bay of Biscay from September.

But maybe after several years of beating and heavy cruising, one type of constructions ends up in better shape.

And i was curious about the construction approaches overall.

Thanks to all for your feedback.

[44'cruisingcat]

Originally Posted by valhalla360

A lot depends on the intent.

Balsa and chopped strand can produce a very strong very long lived boat but likely not a high performance boat (of course there are exceptions to that).

Chopped strand glass doesn't belong on a cat. Or any boat really. JMHO.

[Catmandu]

For resins: epoxy best, then vinylester then polyester

For Laminates: carbon fiber much stiffer than FRP some builders add Tarwon (Kevlar) under water line - great for punctures, harder to repair.

For core: high density foam core is better than balsa core, solid (no core) below waterline - some builders do this, some say it makes the boats heavy.

For layup vacuum bagging is better than wet layup, controlled post curing best (e.g. Autoclave)

Male molded vs female molded. More of an issue of manafacturing costs ...(tooling vs fairing finishing costs)

I read an article interviewing various naval architects that concluded that for cats carbon/epoxy was the lightest stiffestest then cold modled wood epoxy (WEST) systems then FRP/expoxy then FRP/Vynlester then FRP/poly ester

There are hundreds of variables and trade offs that determine the final product and you can experience this for yourself if you go out and sail different boats in big wind and seas.

What you want is the lightest, stiffest structure with most waterline you can afford.

There are huge diiferences in the execution from various builders and you typically get what you pay for ... oh, and the costs increase by the cube of the waterline ...