Fibreglass sail boat bulkhead repairs

[Pigeon_Droppings2]

If there's a lot of pressure on the stand, the hull can deform locally when you take the internal stiffener away.

That was a big worry that I had...there are 2 props just behind the main bulkhead (in line horizontally with 6&7) so I suspect removing the stiffeners in this area would likely result in movement.

Woke up this morning having second thoughts about the whole endeavour!

This boat has a fixed keel which makes recovery a bit of a faff...I need to decide if it's worth putting so much time into it.

 

[Misterg]

there are 2 props just behind the main bulkhead (in line horizontally with 6&7) so I suspect removing the stiffeners in this area would likely result in movement.

It's not the end of the world - as long as you're aware of it, you can check and move / adjust the props as required - the hull will spring back as long as you haven't removed all of the bulkheads. It's not a hard or 'risky' job to do, just potentially dirty and unpleasant!

Resist the temptation to replace anything you don't need to.

I would **guess** at about a day per bulkhead to start with (by the time you've cut the old one out, cleaned up the remaining structure, patterned and fitted a new piece of ply, glassed it in and cleaned up) - maybe two per day once you get into your stride.

(Our first one was a bilge keeler on a trailer, and I had the luxury of being able to put it at the bottom of the garden while I did the repairs.)

If it's an old boat that you're not emotionally invested in, it would be a lot less work to find one in better condition!

 

[Misterg]

Passing thought: You could probably save quite a bit of time by making lining paper / card templates of the existing bulkheads before you knock the old ones out. You could then cut the new ones (or at least rough them out) in advance.

 

[Pigeon_Droppings2]

Passing thought: You could probably save quite a bit of time by making lining paper / card templates of the existing bulkheads before you knock the old ones out.

That's a very very good idea I think...especially for the curved sections.

Having decided I was going to walk away I think I'll do a 1 day trial to see how I get on and go from there.

Worst case is there will be a free boat and trailer available!

 

[Keith 66]

If you need to fit a bulkhead or any irregular shape anywhere you can use a Spiling board & Tick stick, heres a link that shows how its done, http://www.unlikelyboatbuilder.com/2013/05/when-youre-ready.html, It is simple fast & very accurate.

 

[addjunkie]

Woke up this morning having second thoughts about the whole endeavour!

This boat has a fixed keel which makes recovery a bit of a faff...I need to decide if it's worth putting so much time into it.

Having decided I was going to walk away I think I'll do a 1 day trial to see how I get on and go from there.

Worst case is there will be a free boat and trailer available!

The trailer will have value even if you use a gallon of petrol and matches to remove the boat

This boat has a fixed keel which makes recovery a bit of a faff...I need to decide if it's worth putting so much time into it. If it's an old boat that you're not emotionally invested in, it would be a lot less work to find one in better condition!

One of these would tick all the boxes and save a load of plastic bottles being wasted.

BTC-22 – BYD Naval Architects

 

[Pigeon_Droppings2]

Theres no power at the boat site...have to say being able to do this was pretty useful.

The car charger at 7kw AC to DC so I imagine it can do the same in reverse. I haven't tried a mig yet but might be a cheaper alternative to renting a generator...just rent an EV.

 

[Pigeon_Droppings2]

Had a couple of hours this afternoon on the bulkheads...a lot of hammering and cutting later!

I'll need to go over it with a grinder and flap wheel but so far I'm quite happy.

 

[Keith 66]

It looks good so far! What is the keel area like? boats like that are highly stressed in that area.

A cautionary tale... Bloke in our Club bought a 29ft Westerly fin keeler a couple of years ago with intention of doing it up, got it mostly done but ran out of steam.
Sells it cheap to a young lad a few weeks ago who was going to sail it home down the south coast. It is launched & is standing alongside the wharf on its keel, He notices the floor moving & squelching noises, Floor boards are ripped up & all the matrix of stiffeners has broken away from the hull.
No survey. Seller does the right thing & returns the buyers money but is now facing a choice between breaking the boat up, or a repair job almost certainly costing more than the boat is worth.
Old low value boats are cheap for a reason, in fact in many cases they are absolutely worthless.

 

[Pigeon_Droppings2]

It is launched & is standing alongside the wharf on its keel, He notices the floor moving & squelching noises

Can easily happen I think...this one is standing on its keel on a 4 wheel trailer so hopefully it's good.

There's facilities at the marina to lift her if needed to remove the keel but hopefully that won't be necessary.

Tmrw I'm planning to clean up the tabbing areas with a power file and grinder...anyone any idea what width tabbing should be used. I'm thinking measure what's been exposed and then maybe add an inch each side?

I'd like to get the bits I've removed replaced before taking any more out....need to keep some reference points I think.

 

[addjunkie]

Another place to check is the location around the mast foot. Seen a few of those spongey.

 

[addjunkie]

It looks good so far! What is the keel area like? boats like that are highly stressed in that area.

Grounding them at speed doesnt help either……

Old low value boats are cheap for a reason, in fact in many cases they are absolutely worthless.

Bring
Out
Another
Thousand.

 

[Pigeon_Droppings2]

I've been told the happiest moments for a boat owner are when they buy and when they sell their boats.

 

[Dozzer]

isn't that the old rule.
if it flies, floats or fornicates, always rent it

 

[Misterg]

anyone any idea what width tabbing should be used

In the absence of any other advice, I'd copy what was there - probably something like 2-3" onto each surface (so a 4-6" wide strip to start with).

I think the 'gold standard' is to use some sort of filler (e.g. thickened epoxy) to add a fillet to the joint before applying the bonding/tabbing, but I would be surprised if this had been done originally.

If you're using epoxy, use it to seal / prime the new ply end grain and areas that will be glassed (or even better the whole thing) and fit it while the epoxy is still somewhat tacky (or wash it to remove any amine blush if allowed to fully cure).

 

[Keith 66]

Re width of tabbing, Approx 60 - 70 mm on each side is usually about right, 2 layers of 450gm csm & maybe another narrower layer on top, we used to sand the surface veneer off with a sanding disc to expose the inner veneers. Filler was sometimes used & one was Crestomer but its not essential. Some say that you should set the bulkhead on a foam fillet to avoid hard spots but i dont think it makes a huge difference really.
It is true that sometimes the tabbing can shrink if done heavily & fast & create a visible shadow on the outside of the hull.

 

[Pigeon_Droppings2]

Cheers for the advice...I'm thinking the same on the tabbing, measure the original and then clear an extra inch on each side to make things easy.

As suggested I will seal the ply end grains fully. I had a plan of laying a bead of sikaflex 298 (or similar pu adhesive) to act as a spacer under the edges.

Also I'm going to round the joins with a filler...at least for the first few to make my life easier while I'm learning.

2-3 layers is what I was thinking too...maybe 6/5/4 or something like that.

I spoke to a guy at the marina yesterday who might just take it off me in which case I'm off the hook....but at least I have a plan B now.

 

[Pigeon_Droppings2]

Little bit more progress...basically just did a cleanup....I went a bit overboard but I'm anticipating my glass laying being a bit of a mess.

I still need to wire wheel it...I left the centre line as a guide.

 

[Pigeon_Droppings2]

Also measured the existing tabbing...bit surprised at how small it is but I think these are probably just deck stiffeners to prevent movement...about an inch and a half roughly.

 

[Keith 66]

Re Marine Plywood, Just opened up a buoyancy tank on a Bay Raider for a customer, Boat is a 19ft daysailer with good performance & good reputation for performance & build quality. Built from good quality marine ply & epoxied at build.
One of the tank tops that doubles as side seating has cracked & water got in & the panel has gotten a bit punky.
I cut the damaged area out & its a simple matter to scarf a new section in.
Except its an oddball thickness of 7mm, Two firms who will sell you good ply, Timbmet sell Brynzeel except minimum order of ten full sheets! other firm that supplies decent marine ply you can trust is Robbins in Bristol, says on their website will sell part size sheets Dont do 7mm at all & wont part an 8mm sheet So its a full sheet or nowt, A sheet of 8mm Robbins elite ply is £92 then there is £225 delivery & £63.38 in vat taking it to a grand total of £380.30.
I will tell the owner to sit down before i tell him the bad news!
Now going down the boat shed to sort through a pile of secondhand bits & see if i can stick some together.