thanks for the input Roy, much appreciated
I just spoke with mike who makes the boats and he confirmed the transom boxes are plenty strong enough
my kids are lighter than cheese puffs so i think pulling them up will be no problem.
i think filling the base of the aframe with sealant should be fine and having a drain hole or sealing at the transom box. will give it a go and see what happens.
the option of having the wire out of the front of the transom box is indeed an option but given hindsight i would still do it the way i have done so as to prevent unsightly wires and being exposed to possible damage
also on tow points.....i have 3 lifting points on the boat for craning and on the transom these double up as towing eyes as well so should present no issues there