Rebates on deck planks

[aznarepse]

Hello to everybody,
I am about to replace the teak deck on my boat. The boat has a polyester GRP deck with screwed planks and, unfortunately, a lot of leaks. After a lot of research in this subject, I have concluded that I will seal the GRP deck with a laminated of glass fibre and epoxy, bond the new teak planks with SP Systems Spabond 370 and seal the seams with WKT.
There is however one thing that I cannot find information about; probably is plain basic and I am sinning of innexperience and ignorance in this subject.
I am going to use 45x12 mm teak strips parallel to the sheerline and my intention is that those strips be uninterrupted along the length of the teak deck.

The question is:
Should these strips have rebates on the edges?
Could someone inform me about the advantages/disadvantages of the rebates?

I reckon that after many years, the seams will be reduced due to wear, thus better without rebates?

I include a pic of the deck as it is now (32 years old). Note the uninterrupted strips which I would like to reproduce again.

Many thanks in advance.

 

[Seanick]

Yes you need rebates. To make the seam sealant perform correctly it has to be square, i.e. 6mm by 6mm. Read the sealant instructions carefully, eg Sika 290DC.

Is the boat Duallist?

 

[aznarepse]

Thank you!
As I said, it had to be plain symple and I was just missing it. It makes sense; the tensions in expansion of the sealant would be better distributed within the material.

Thanks again.

 

[aznarepse]

Sorry! Forgot to mention.
She is a Belliure Endurance 35. She was built in Spain, GRP hull.
13 t displacement.
I love her, but, of course it is my boat!

 

[Tranona]

Would seriously question glueing the teak to GRP. In fact the sensible thing would be not to use teak at all but to just finish with glass cloth and epoxy and then paint. Then you will have a watertight deck unlike the leaking thing you are just getting rid off. However if you do insist on teak then it should be bedded on a flexible sealer/adhesive such as Sika without any fastenings, with a caulking seam filled with Sika. This is difficult and expensive to do properly.

Do not glue to the deck with epoxy as the differential expansion of the teak of the thickness you are proposing compared to the substrate will almost certainly lead to a failure of the bond as well as movement between planks to push the sealant up.

There is no satisfactory way of attaching teak to a stable GRP substrate. As you have discovered screwing leads to leaks. Epoxying leads to a flexible wooden deck attached to a solid fixed GRP deck. The latest method is to pre-form the teak deck and vacuum bag onto a flexible bonding agent such as Sika. It is too early to say whether this is effective long term.

 

[westsailaway]

Hi Aznarepse,
I've a Westsail 32 with a similar situation as your Endurance. Seems most Westsail owners remove the teak deck, epoxy in the fixing holes and glass fibre/paint followed by a durable stick on decking. See the Westsail website for details. I am still holding on to my teak deck(36years old) with worn away seams and plenty of teak oil which has sent it black,repels moisture,preserves and seals. Due to excessive cost and technical issues I recommend you avoid laying a new teak deck as there other better options.