Questions for spetre owners

[Bushwacker]

ab1111 - it'd probably work pretty well - same basic idea as I had, only you're saying to apply the silicone to the deck opening, which would provide more surface area to stick to than the hatch. However instead of your wood sticks, why not just coat the bottom and sides of tank hatch lip with some paraffin-type wax like Strick uses for his molds. Then your silicone "gasket" is literally molded to the tank hatch!

One caution about thickness of the silicone "coating" - something I learned from 35 years in the aerospace business is that bond strength of any coating is inversely proportional the thickness. In other words, the thinner that silicone "gasket" is, the better it will stick and the more durable it'll be!