Boat Rebuild

[Bug]

I have a 21 foot mono hull which i have started to rebuild/restore. she is an old boat and alot of work is needed, transom needs replacement, decking needs replacement, floatation bottles or foam need to be replaced and more.
i need some help with the following,

what foam can i use to fill the hull, and does she also need bottles or will foam be ok?

how much foam/bottles is/are needed to stay afloat?

the old transom was made of teak, what can replace it and what thickness?

how can i find out what HP engine to place on the back?

 

[Rory]

to start off with weigh the boat on a weigh bridge so you know what its weight is taking into account how many crew you are going to want 1 per meter of boat so for you 6@85kg per person then add on the weight of your motors and fuel
for example

boat 700kg
motors 250kg
crew 510kg
fuel 100kg

total 1560kg and you nedd 60% boyency so need to put in 950lt of expanded foam or equvelent bottels. as for the transom must use marine ply 21mm which you sandwich together to double up with fiberglass, 2x 90 are good for a 21 would not go less. PM me if you have any other questions

 

[Rory]

foam is a RX1 expansion foam 2 part A and B

 

[Klipdrift]

I recently completed a similar project with my boat, with exception of the transom. The Transom would have been one step too far and I would have looked for another hull with a decent transom.

Think about it before you start because it is a costly exercise. Good luck.

 

[Bug]

thanks for the help, the transom is well lets say, finished, i can crush it with my hands, seems like water came in and the wood had been destroyed.
could you place marine ply inplace of it, 3 sheets to make up +- 2 inches or 5 - 6cm

 

[Rory]

yes