An excellent and thought provoking topic Garry
These plastic boxes have come a long way recently in terms of refinement and the quality of the fittings included. They are inexpensive and save a lot of hard work with the advantage of being easily replaceable etc. However it seems to me from the previous comments that these boxes still have too many issues resulting in potential water ingress which scuppers the running of the boat. Those with dual seals are compromised due to the fact that lid bolts go between the inner and outer seal, such that in a dunk situation water will flow into the mid section (through the bolt holes) leaving only the inner seal to keep water out.
For me personally I will now always stick to the old fashioned way... by making a bespoke radio box. Okay, it takes ages to do a good job and longer than most would have patience for
But the advantages pay dividends I think. The advantages are:
1) You can have the box exactly where you want it.
2) No need to worry about plastic splitting.
3) You can make it big for extra boat buoyancy.
4) Make the flange strong and it won't twist when you tighten the lid down.
5) Use a Polycarb lid, instead of perspex with plenty of bolts and you have a tightly clamped fit without the risk of (perspex) fracturing.
My Crusader boat at Stevenage this year flipped over 3 times in one race and was submerged for good while in the process. When I got the boat home it had not a single drop of water in the radio box.
These two images show how that box was done: I realise that few folks would mess about like I do on such things
It explains why it takes me for ever to build a new boat
Food for thought?
Craig