I'm on a bit of a quest to get my forward locker dry. So far I have identified/remedied 6 sources of water ingress:
1. Locker hinges are not very well embedded in Sikaflex causing leakage.
2. Twist locks are also not very well embedded in Sikaflex again causing leakage
3. The twist-lock shaft has a O-ring to keep the water out, it needs regular replacement. Southco (the manufacturer) has no service-sets, they expect you to buy new ones)
4. The Harken switches have a design-flaw. The top part (the part that has the movable lid attached to it) suffers from deformation at the screwholes causing the circular rubber part that you press to activate the switch to no longer be waterproof. The rubber is sandwiched between the top and lower part but the pressure on this rubber after some years is no longer even distributed because of deformation of the top part (see enclosed pictures).
5. The composite disc on which the Harken switch is mounted is not very well embedded in Sikaflex causing leakage.
6. The stainless tube that ducts the furler electrical cable below-decks is not very well embedded in Sikaflex causing leakage.
Also be aware the holes trough the deck have exposed multiply wood as core material. I found one hole with slightly wet core material.
I'm now awaiting the next tropical downpour to see if the locker stays dry...