Bulkhead advice

[Davidkinton]

I'm getting to the point where I'm starting to fit out my 25ft Buckingham Canal cruiser. I need to install bulkheads to form a toilet compartment and a v berth. My question is, should I fibreglass these bulkheads in first before lining out, as seems to be the case in yachts, or fit them after the lining out as is the case in narrowboats? Any advice anyone can offer is much appreciated.

 

[vyv_cox]

Bulkheads in production yachts are installed before the deck is attached to the hull, as they are too big to get through the companionway afterwards. The old method of fibreglassing bulkheads in has now been superseded by attaching them using filled epoxy paste, making a much tidier and stronger joint.

 

[PuffTheMagicDragon]

If they are structural they are bonded directly to the hull. If they are only to provide some privacy they are no more than a 'partition' and may just as well be installed after the lining, leaving a small clearance, as is done on some small Dehlers and other boats.
This last method has the advantage of being reversible. However, if you are certain that your layout will be permanent, there is no reason why you should not go for the 'permanent solution. If you go for this solution consider fitting a narrow strip of rigid foam (as is used in sandwich construction) between the edge of the bulkhead and the hull before applying radiused GRP strips to each side so that you avoid stress points and visible lines on the outside. Cutting a shallow 30mm wide rebate round each side of the bulkhead edge will give you space for the GRP tape and will help to give a neater result.

 

[ex-Gladys]

Noooooo.... Gladys was fitted out by Severn Valley Cruisers, and it's impossible to do a decent replacement job where the lining goes behind fitted woodwork

 

[Davidkinton]

Thanks for this. They are not really structural, and as such probably lining out and then installing bulkheads would be eaisest?

 

[ex-Gladys]

Thanks for this. They are not really structural, and as such probably lining out and then installing bulkheads would be eaisest?

Neither's 3/4 of Gladys' internal woodwork, but in anyone's language it's a badge headlining first

 

[vyv_cox]

but in anyone's language it's a badge

Bodge? I agree.

 

[ex-Gladys]

Bodge? I agree.

Bloody predictive... y

 

[Davidkinton]

The foam between the bulkhead and hull, could spray foam be used? Then, trim it back and tab in the bulkhead using fibreglass tape?

 

[PuffTheMagicDragon]

Spray foam is too soft and would be awkward to control. The easiest is to buy a sheet of structural rigid PVC foam, the type that is already semi-separated into squares. This (usually) has a backing of glass-fibre 'netting' on one face. Cutting it along the groove between the squares will give you strips that are very flexible in one plane and that can easily be wedged between the bulkhead edge and the hull.
Your fibre-glass supplier will probably have it in stock. There are various brands that make them.
They would be something like this:

This is my opinion; others might not agree.

This is the usual construction when the bulkhead is structural. In your case the hull, already built, does not need strengthening in that area so your application of glass tape can be much lighter than what is shown in this diagram:

 

[Davidkinton]

Thanks for the advice. Bulkheads, foam and tabbing it is!