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Brent. I too took a ride on Atlantis, and checked out the hatch very
closely. The ring groove on mine will be on the bottom ring, where it will
be subject to abrasion from entering/exiting the sub. I did it this way because
I wanted the thicker flange ( with the groove ) to be part of the hull. A
lighter ring on the hatch makes it weigh less, and the heavier ring on the hull
adds strength to the hull opening. It's a trade-off. I don't anticipate
replacement of the ''O'' ring to be a big deal, and in fact may be a good idea
to replace on a regular basis so the groove can be cleaned more often.
Some of the subs I've seen have relatively thin flanges, but they all
have a tower to add strength. I am trying to minimize the tower height to aid in
dropping the hydro drag. My testing showed me that with bigger ballast tanks, I
can achieve reasonable freeboard height without a tall tower. I also want to
keep the top half of the sub as light as possible, to keep the center of gravity
low and the center of buoyancy high.
I will however need a splash guard to keep waves from washing over
the open hatch.( still working on that design.)
I think ABS calls for 30 inches minimum, but I won't get that much at the
hatch. I'm making the hatch opening rise above the hull by only 2
inches, so a splash guard that lays flat when submerged is what I'm working on.
I have some ideas, but haven't spent a lot of time on that yet. I'm
leaning toward an inflatable device like maybe an inner tube type affair,
to deflect the waves but also have some ideas to have a plexi screen that would
pop up when I'm surfaced. I will be able to get the 30 inches with
whatever the final design ends up being.
My hatch flanges are pretty thick, and so are heavy. The hull ring is
1-1/2 inch thick X 2 inch wide while the hatch ring is 1 inch X 2 inch. The hull
dome is 3/8 inch like the hull but has a taller radius than the lid I'm cutting
out of the hull for the hole. The tower is only 6 inches long overall, giving me
just enough tube on the inside to attach the inside stiffeners and
gussets to. Frank D. Get a sneak peek of the all-new AOL.com. |