Wet Bag Vs Vacuum Bag Build For Catamaran

[SAILOR911]

Can someone tell me the pros and cons of each method of construction using;
Core cell foam, epoxy, carbon mat, and e-glass?

I am seeking complete fill/penetration of the epoxy through carbon and e glass. And light weight on catamaran over 50'

Wet bag vs vacuum bag construction

[Zach]

Need more information:

One off, or production built?

Male mold or female mold?

Gel-coated mold, or a station/rib band mold over a strong back with heat formed foam as the work surface?

[SAILOR911]

Need more information:

One off, or production built? PRODUCTION

Male mold or female mold? FEMALE MOLD

Gel-coated mold, or a station/rib band mold over a strong back with heat formed foam as the work surface?THIS ONE I MUST CHECK

THANK YOU FOR YOUR REPY

[Stumble]

First there are construction methods, then materials.

Carbon/e-glass/s-glass are material choices and have to be selected early in the process because the engineering is different.

Epoxy/polyester/vinylester are material choices and also need to be selected early in the process for engineering reasons.

In large part the material selection is driven by price. Carbon/epoxy is the most expensive, but also the lightest and stiffest.


Then you have handeling details. In order of engineering preference you have prepeg, infusion, vacume bagging, wet layup. But that's also pretty much the order of cost, with prepegs being massively more expensive than any other method (it typically also requires post layup curing in an oven).

Then there are core material selection. Nomex honeycomb, foams, balsa, plywood, etc. these also run the gamut in price. With Nomex honeycomb at the normal high end (you can get into some massively more expensive stuff if you want) and plywood at the low.

Then there are build methods... Male molds, female molds, strip planking, there are a lot of ways to build a boat.


All of these selections impact on the rest. Once you go high end in one place you almost have to go high end elsewhere to retain the benefit.

Do you have a question about a specific build method/material process?

[FSMike]

Lol.
Do I assume correctly that "wet layup" is what the op meant by "wet bag"?

[Zach]

Originally Posted by FSMike

Lol.
Do I assume correctly that "wet layup" is what the op meant by "wet bag"?

Wet layup by hand then put under vacuum. Slang...

[Stumble]

Originally Posted by Zach

Wet layup by hand then put under vacuum. Slang...

Since he asked about both 'wet bag' and vaccume bagging, I presumed there was a difference since I have never heard of 'wet bag' before. Different ways to refer to the same thing I guess.

[GRIT]

I have built 15m catamaran using resin infusion. I would highly recommend infusion (dry bag) over hand layup and vacuum bagging.

I have infused Carbon fiber up to 6mm thick, and glass up to 10mm thick.

If you have any specific questions, feel free to PM me.

Paul.

[SAILOR911]

Paul

I would greatly appreciate a discussion regarding building a cat.
Please contact me. What is PM?

I intend to contract the construction. I am discovering the many pitfalls of marine construction and warranties; it is more dangerous a mine field than building construction .

How would you suggest to begin our discussion?

Thank you for your time and effort,

ron

[GRIT]

If you wish to discuss privately, you may e-mail me at my username (sv******na) @gmail.com.

I must forewarn you, I built our boat myself. I have no experience in hiring builders. There are others on this forum who have done that, and any one of them would be a far better resource regards hiring a builder.

Cheers.
Paul.

[dannc]

Originally Posted by SAILOR911

...
I intend to contract the construction. I am discovering the many pitfalls of marine construction and warranties;
...

I would suggest getting a subscription to Professional Boat Builder, Professional BoatBuilder Magazine - Written for boatbuilders, repairers, designers, and surveyors, and then buying their complete collection of back issues, Professional BoatBuilder and start reading. The index will be your friend.

Originally Posted by SAILOR911

...
it is more dangerous a mine field than building construction .
...

Yes, yes it is...

Later,
Dan

[Stumble]

Where are you planning to build? There are some exallent one off yards, but obviously some terrible ones as well, and the bad ones can open and close then be reoperati G weeks later.

I would recommend speaking with the designer and getting his recomendations for build yards as well.

[Lucky]

Originally Posted by dannc

I would suggest getting a subscription to Professional Boat Builder, Professional BoatBuilder Magazine - Written for boatbuilders, repairers, designers, and surveyors, and then buying their complete collection of back issues, Professional BoatBuilder and start reading. The index will be your friend.



Yes, yes it is...

Later,
Dan

I'm shivering down my spine from the suggestions of very complex amateur building! Unless you work with a very competent designer and builder you will spend a lot of money and energy on what could end up as a disaster! Building a catamaran, due to the very complex strains on the boat compared to a monohull, means that the possibilities for failure massive.

Another issue with building such a complex boat is the resale value. Always have that in the back of your head! I lot of people say that they will be keeping a house or a boat for life and do not consider market value. You might end up in a situation that a forced selling off slams you. Then if you own a well known production yacht that might not be a problem. In Europe a self built cat is sale-able for a pittens only, even if well built.

I admire the people who take on the challenge of building their own cat, I've seen a few when I lived in Australia where self construction is more seen than in Europe. But, the resale market is very restricted.

Good luck in you chase for the optimal cat and if you choose to self build best of luck!

Happy lead free sailing from Lucky

[catman]

I believe that wet bagging might be another term for the infusion process. The complete layup it's assembled then vacuum bagged. The vacuum bag has tubes on one side attached to the resin supply then the other side has extraction tubes attached to a vacuum pump.
Once the assembly is flooded under vacuum pressure it will start to exit the assembly, and voila you have a system with the least amount of resin infused in.
Dry bagging is where the components are layed up with a slow flash hardener in the resin and then covered with a vacuum bag to exert pressure on the whole assembly, no extraction of resin taking place.
I was witness to my friend building hard hulls for the US Marine Corp's inflatables
And they specified the infusion process for maximum strength and light weight.
Catman

[DerekKelsall]

Originally Posted by SAILOR911

Can someone tell me the pros and cons of each method of construction using;
Core cell foam, epoxy, carbon mat, and e-glass?

I am seeking complete fill/penetration of the epoxy through carbon and e glass. And light weight on catamaran over 50'

Wet bag vs vacuum bag construction

Today I have received a pic of 39ft., tri Aqua Blue. Owner built and launched 40 years ago. No structural issues, good for more decades, 1.5 repaints and rigging replaced once. The spec, which is good today - Cross linked PVC foam, uni E-glass and polyester resin. Sailed for at least 3months each year, mostly in the Med. The method does not restrict resin choice. Vinylester is some builders choice. Epoxy is too toxic for me to recommend for any cruiser. No builder wants to wear all the protective gear recommended by the epoxy suppliers every time entering the workshop.

Today, KSS uses a full length table and resin infusion. Let no one deter you from resin infusion. Learn in 2-3 days and enjoy neat clean and best laminate. full size panels ensure fair lines and that lovely smooth finish from the table costs nothing. No compromise, Round bilge hulls. DVD available -contact <derek@kelsall.com>

happy boating

Derek