HI All
We found that sitting the deck on first(hull upside down) and marking out both sides of the hull frames onto the underside of the deck.
Mask up this area and coat the rest with thin layer of glue or fibre glass resin will waterproof the under deck.
This will stop the deck delaminating in years to come!!!!!
I like the idea of installing the spray rails before installing the deck.
I also install the motor and drive line before installing the sides.
Also if adding floors cut these to fit before installing the sides.
I did this on my Sea Hornet which I built last
year(see modelboats forum Sea Hornet 2015).

Fantastic thanks for that I was starting to get confused. I will post pics soon

Yes, that's providing that they are only just large enough to do that.
But if they are large enough to slightly over lap both bottom skin and the deck stringers, then trim them flush with both bottom skin and deck stringers.
This way you will get a better finish.
Then fit the decking and you can then trim this along the top of the side skin.
Then rub down with sand paper to finish off smooth.
You can then fit the spray rails along the side and bottom skin join and the top
rubbing rail along the join of the top of the side skin and the edge of the decking.
Then you are ready to dope the hull to water seal it.

Thankyou tom when you say you fitted the side skins do you meen. fit them so they are flush with the deck, then trim them to fit flush with the bottom skins. thankyou

I don't know if anyone else has replied, but I have built several Crash Tenders in the past with my father back in the 60's.
And also built a couple of Sea Hornets and a Presedent Fairy Huntsman in the 70's and a shrunken down version of a Crash Tender (28")a couple of years ago.
I have always put the bottom skins on first and then trimmed them to the edges of the side stringers.
Then put the side skins on and then trimmed them to the edges of the bottom skins.
After this then fitted the side spray rails. I have found this to be successful.
So I hope this will help you. if any one else could give you a better way then you could take their advise.
Good luck but I'm sure you wouldn't need it. Hope all goes well and keep us informed on how you are doing and hopefully you will post a few pictures on how you are getting on so we can see.
I'm sure you will get plenty of advise and great comments on the progress of your model from it's pictures on your build.
Regards Tom. alias BOATSHED