Reinforcing flotation tanks (deck seating area)


New Member
I have a classic, a very early 1967 Vanguard 470 and have a question:
How do I fix a little softness on the seating area on top of the flotation tanks?
It is not delamination of fiberglass, but a little bit soft from stress.
470 class rules mention that we cannot add any material with the intent to increase stiffness, but in this case, the boat at one time was sounder than it is today, my objective is just restore the original stifness.
Does anyone knows how to fix this without violating the class rules?
Can you reach the area(s) to be reinforced via an existing inspection port?
If yes remove the port including the outer ring, if not buy a new inspection port and cut the correct size hole.
Beware: Foam flotation blocks may be in the way of where you want to reinforce.
Use a mirror and flashlight to look.
Do not install the port yet; you do NOT want to get glass on the threads of the port.
The following is best done with the boat hanging upside down at good working level.
Clean and wipe down with Acetone the area to be reinforced.
Add the layer(s) of glass
Reinstall the inspection ports.
thank you Bill for your reply.

All you said makes a lot sense, I may have to add another inspection port aft on both sides where the helmsman seats to have access to reinforce, I liked you mention that is best to work with the boat upside down, I was thinking on this. I was just wondering how much reinforcing I am allowed to do to can keep the boat race legal.