Fiberglassing over a composite trimaran

[captlloyd]

That small trimaran could be a fun little boat, fast too. I recommend you find someone who knows more about boats and boat construction to have a serious look at it together. Get on YouTube. There is a ton of information on there about plywood boats and glass over ply.

[sandy stone]

Originally Posted by nuvaslacker

Be careful with the weight increase; fibreglass with resin is much more weighty than you might think; a 25' tri is likely to be very, very weight sensitive.

What he said!

[JeffH001]

Originally Posted by JC Reefer

PICTURES! We demand pictures.

Everyone starts somewhere but we won’t get anywhere going at this rate.
Pictures will go a long way.

Something close up. Also if that are any areas where material have been scratched, scrapped or torn then we could use some close up shots as that would give some good clues as the the design material.

The current owner/seller has newly painted two part epoxy paint inside and out on this professionally built Searunner 25 with 7ply and 9ply marine plywood.

I've attached a closeup photo.

[JeffH001]

[JeffH001]

http://mongrelfxcom.ipage.com/mongrelfx/SeaRunner25.JPG

[Fore and Aft]

Cheechako you might want to check out RM yachts before you start knocking glass over plywood yachts! Nothing wrong and nothing cheap about the RM yacht range. In my opinion they are a pretty sweet looking monohull.
RM890+ - RM Yachts

Cheers

[JeffH001]

Nice boat. But for my first boat I’m not looking to spend more than $10k. I’ve seen other used monohulls in great looking condition with trailer for about 7 to 8k.

Also, I would rather get a trimaran first, over a monohull, more for stability reasons and a lot more exterior deck space between the main hull and the amas on both sides.

[boatman61]

In my case I put 3 coats of epoxy on the ply then laid 4oz cloth while 3rd was still wet then finished with 2 more coats of black dyed epoxy..
Oh.. and that was with West System.

https://www.cruisersforum.com/forums...icture9390.jpg

[Dsanduril]

Many Searunners were built with plywood and polyester, some were built with plywood and epoxy. Most had a layer of exterior glass. Getting details of the exact build is pretty important. For way more information than you might want you can take a look at this thread. The thread is pretty active, you can easily ask specific questions.

The critical thing is maintaining the waterproofing, so check carefully for rot. Since most of these were homebuilt build quality is variable (I see the seller told you "professionally built", in which case I would ask "built by?"). There are some 40-year-old Searunners going quite strong and others that have long rotted to nothing. They are fun and enjoyable boats when in good shape and not overloaded.

[jimbunyard]

Originally Posted by JeffH001

Hi All, I’m quite new here.
I’m looking to purchase my first 25ft Trimaran. It’s a composite build, but I was thinking of fiberglassing it all over to make it more durable.

I wanted to get some advice on doing this.
Is it worth doing?
Do i need to strip it back down the plywood before applying fiberglass?
Would carbon fiber work?
How much fiberglass & epoxy will I need?
Has anyone done this before?
Are there any books or articles you could point me to?

Thanks.

'Professionally' built does not mean that it was built to high standards, only that someone was paid to build it.

If the boat wasn't built with the outside of the hull encased in an epoxy/fiberglass layer, preferably vacuum-bagged, and after construction was only painted with an epoxy paint, any and all joints will fail sooner rather than later due to the unequal expansion of the two materials. If this is the case, this is a valid place for the oft-repeated advice 'Run'.

If you are only talking about glassing the interior, to just 'paint' it with a single coat of epoxy, figure at least 20-30 gals at 100/gal. for epoxy, plus labor and other materials (sanding, application, safety).

To do it right you need to add some type of cloth, at least in certain areas (at minimum) because resin alone has little strength, and stresses at sea will quickly crack un-matrixed resin. Double the resin (if you plan on reinforcing all the coated areas) and add the cost of the reinforcements, plus the added time for labor to apply.

As a further 'questioning factor', included is your original picture, plus two closeups that reveal the level of 'professionalism' in the boat's construction.

The first is the mostly untreated exposed edge of plywood, adjacent to what appears to be a pad for an outboard motor bracket (also singularly poorly finished), as evidenced by the rough, unfilled surfaces and exposed fastener heads.

The second is an example of the same; a poorly sealed exposed plywood edge of the cabin top.

Without knowing more about the boat, all this is obviously speculation, but from the single picture given---a certain amount of skepticism is certainly warranted.

[Jim Cate]

Originally Posted by jimbunyard

'Professionally' built does not mean that it was built to high standards, only that someone was paid to build it.

If the boat wasn't built with the outside of the hull encased in an epoxy/fiberglass layer, preferably vacuum-bagged, and after construction was only painted with an epoxy paint, any and all joints will fail sooner rather than later due to the unequal expansion of the two materials. If this is the case, this is a valid place for the oft-repeated advice 'Run'.

If you are only talking about glassing the interior, to just 'paint' it with a single coat of epoxy, figure at least 20-30 gals at 100/gal. for epoxy, plus labor and other materials (sanding, application, safety).

To do it right you need to add some type of cloth, at least in certain areas (at minimum) because resin alone has little strength, and stresses at sea will quickly crack un-matrixed resin. Double the resin (if you plan on reinforcing all the coated areas) and add the cost of the reinforcements, plus the added time for labor to apply.

As a further 'questioning factor', included is your original picture, plus two closeups that reveal the level of 'professionalism' in the boat's construction.

The first is the mostly untreated exposed edge of plywood, adjacent to what appears to be a pad for an outboard motor bracket (also singularly poorly finished), as evidenced by the rough, unfilled surfaces and exposed fastener heads.

The second is an example of the same; a poorly sealed exposed plywood edge of the cabin top.

Without knowing more about the boat, all this is obviously speculation, but from the single picture given---a certain amount of skepticism is certainly warranted.

Sadly,I must agree with this evaluation. The photo shows a poorly finished boat with lots of construction shortcuts recently covered up with a layer of paint. To me, this suggests a less than forthcoming owner, and would lead me to suspect other cover-ups might lurk. And describing unglassed ply construction as "composite" also sounds a warning IMO.

I wouldn't buy her myself... at any price, including free.

Jim

[JeffH001]

my initial idea was to build a trimaran from plans purchased from the internet, but I felt it would have taken a lot more time and resources and space. When I saw this Trimaran, my intention was to get this as a project boat and fiberglass it myself. which would save me the time and tools it would take to build it from scratch. I’m not worried about putting in some elbow grease to get this properly Fiber glassed. With that being said and knowing I’ll be putting more work into it, I’d like to get your opinion on how much I should look to purchase a Searunner 25 [bare interior] with a trailer currently listed at $8K or nearest offer. Seller was willing to drive it anywhere in the continental US for an extra fee.

[psk125]

He's so eager to get it off his hands that he'll drive it anywhere in the Continental U.S. for you? R U N ! Applying new fiberglass onto paint bonds the fiberglass to the paint. If the paint starts to flake off...so does the fiberglass. Delamination like this opens wood surfaces to absorb moisture, and then rot. This causes boats to fall apart. That is probably not what you had in mind. To make sure you have a good bond with your 'glass/epoxy coating, contemplate having to sand everything back to bare wood to ensure that the 'glass you apply actually sticks. Then, to protect the epoxy from UV, you will have to paint it over again. Others have suggested materials costs of several thousand dollars. That did not include the paint, which besides being pretty pricey is also very finicky about temperature, humidity, and dust. If your workspace is not inside, waiting for the right weather can take a l o n g t i m e. (Painting our deck took WEEKS.) Are you an experienced expert at applying epoxy, fiberglass, and paint? Add something for "operational errors". Perhaps not as much as 10%, but, mistakes can cost you Figure any work will take twice as long as you originally hope, too, if not more. This boat is sounding more and more like a less than viable option.

[JeffH001]

Thank you all!
I really appreciate all the advice and input. I will keep looking and reading.

[coopec43]

Well I think we finally worked it out! The trimaran is actually plywood.


What you trying to achieve by putting a layer of glass over it? As someone has already mentioned it will add weight to the yacht.