Which hull repair method?

[buzzy bee]

Kia Ora from New Zealand.
Could any of you knowledgeable boaties please help me out with info about repairing a 15ft seam-batoned carvel hull ex fishing boat.

My main concern is the structural integrity of the hull and what would be the best appoach to repairing it.

Shes obviously had a hard work life and suffered several damaging blows to the hull. there are around 7 broken frames and 2 or 3 damaged planks (plus some repaired sections), and a slight hog in the hull.
My options are either:
traditional - to replace all damaged sections, re caulk and hope she flooats after taking up, or,
Repair damaged sections then re-sheath in either Fibre glass or veneer cold moulding.

I had a local boat repairer look at it and he suggested sheathing it in fibre glass. He said I would have endless problems with the hull leaking on account of how old and damaged it is.

I have read a lot about the pros and cons of glass and personally would prefer to go the cold moulded veneer option.

Any input or advice would be greatly appreciated.

 

[fallguy]

Is it going to stay on the water or the hard?

Water-fix it traditional.

Hard-glass it after needed repairs or cold mold. The veneer option is a good idea, but I have no experience. I own a cold molded boat. It is 58 years old and operable, but needs a stem repair.

 

[fallguy]

cold molding seems a little late as a repair; so I'd glass

 

[buzzy bee]

Is it going to stay on the water or the hard?

Water-fix it traditional.

Hard-glass it after needed repairs or cold mold. The veneer option is a good idea, but I have no experience. I own a cold molded boat. It is 58 years old and operable, but needs a stem repair.

I will keep it on the hard so probably glass or cold moulded veneer. I think the fibreglass option seems to be the best for water-tightness but Im concerned about trapping moisture resulting in rot

 

[fallguy]

Rot doesn't need much moisture.

You'll need to kill off any decay by removal and then encapsulation will be a bit rough, but you could do the repairs fairly easily on rotten bits with thickened epoxy.

I think West System has some great free info on that sort of effort, but I have not done it.

Often you'll see Chris Craft guys say they have done the bottom in the West System.

Perhaps someone else here can direct you better.

 

[Lepke]

Any fiberglass skin over the planking has to be thick enough to withstand cracking when the hull flexes. That thickness makes the hull much heavier. You end up with a hull inside a hull. The existing planking needs to be refastened so it's tight to the ribs, stem, keel, etc. The planking also needs to be sanded to clean dry wood for the epoxy to bond. Unless you're experienced in overhead fiberglass work, the hull needs to be upside down.
Later the bilge needs to be kept dry. Otherwise the wood rots. I don't know about New Zealand, but here in the US, all wood preservatives that work are illegal and we're left with our great grandfathers treatment - salt. Keep rock salt or borate in the bilge so any moisture becomes heavily salted water.
I've built and repaired many boats and found it's best to remove all the suspect wood before any new work is added. Often when cutting corners, new work has to be removed and done over as later problems are found. It's a small boat. It would be faster, cheaper and easier to build another hull. By faster I mean you'd probably need less than half the hours to construct a new hull. Believe me I've been there and done that.

 

[fallguy]

Any fiberglass skin over the planking has to be thick enough to withstand cracking when the hull flexes. That thickness makes the hull much heavier. You end up with a hull inside a hull. The existing planking needs to be refastened so it's tight to the ribs, stem, keel, etc. The planking also needs to be sanded to clean dry wood for the epoxy to bond. Unless you're experienced in overhead fiberglass work, the hull needs to be upside down.
Later the bilge needs to be kept dry. Otherwise the wood rots. I don't know about New Zealand, but here in the US, all wood preservatives that work are illegal and we're left with our great grandfathers treatment - salt. Keep rock salt or borate in the bilge so any moisture becomes heavily salted water.
I've built and repaired many boats and found it's best to remove all the suspect wood before any new work is added. Often when cutting corners, new work has to be removed and done over as later problems are found. It's a small boat. It would be faster, cheaper and easier to build another hull. By faster I mean you'd probably need less than half the hours to construct a new hull. Believe me I've been there and done that.

They are skinning with epoxy? impregnated plywood or what becomes plywood, that is..

I am not fully familiar with the method, but any glass is not thick that I know of..

 

[buzzy bee]

Any fiberglass skin over the planking has to be thick enough to withstand cracking when the hull flexes. That thickness makes the hull much heavier. You end up with a hull inside a hull. The existing planking needs to be refastened so it's tight to the ribs, stem, keel, etc. The planking also needs to be sanded to clean dry wood for the epoxy to bond. Unless you're experienced in overhead fiberglass work, the hull needs to be upside down.
Later the bilge needs to be kept dry. Otherwise the wood rots. I don't know about New Zealand, but here in the US, all wood preservatives that work are illegal and we're left with our great grandfathers treatment - salt. Keep rock salt or borate in the bilge so any moisture becomes heavily salted water.
I've built and repaired many boats and found it's best to remove all the suspect wood before any new work is added. Often when cutting corners, new work has to be removed and done over as later problems are found. It's a small boat. It would be faster, cheaper and easier to build another hull. By faster I mean you'd probably need less than half the hours to construct a new hull. Believe me I've been there and done that.

Thanks for your advice, do you think this hull is not worth saving? what are your thoughts on veneer cold moulded over the repaired hull, then sealed with epoxy for watertightness so as to stop the planks taking up, also keeping the boat on the hard so its not in the water for long periods?

 

[gonzo]

You can build a thick laminate over the hull and get some more use out of the boat. I have done that in several workboats. However, the wood will continue to deteriorate. It looks like there is no interior joinery or deck and maybe no engine, so it makes it of little value. Usually, the hull is maybe 10 to 20% of the total value.

 

[BlueBell]

I know a guy who did this successfully with lots of acetone and then west system.
It's held for years.

 

[pauloman]

use a flexible epoxy and epoxy inside and outside of the hull (not just one side). As you are not in the USA, I cannot recommend epoxy options that you could purchase.

 

[ned L]

This thread is a bit dated, but someone brought it back to life a couple of days ago, ... so here goes.
Very pretty little hull! and nicely built.
For any 'sheathing' option, repair work should be done first, to put things in order, so why not repair her properly? She is riveted batten seam construction, so she would not open up very much on a trailer. Will she be a dry bilge boat if trailer sailed??, ..... "No", but sometimes part of having a vintage boat is also in understanding it. Properly rebuilt and she could go another 50 - 75 years easily. Sheath her and she will probably be on a downhill slide within a decade.
I guess it all depends on what you want her to be.