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Positioning Handholes & Deckplates

While some locations will be clear and obvious, it's easier than you may think to get it less than ideal. Take the deckplates in an ama for example. They are typically needed to vent and sponge out any water at a low spot, but occasionally also for access to mounting bolts for the akas (cross beams), as on the W17. That's when 'location' can become as important as for real estate. If you check out this photo, you'll see that if they are closer than 200 mm to the bolt, it will be difficult to bend your wrist enough to reach it. So in such a case, make sure the center is at least 250‑300 mm away. That may not be possible for the aft mounting but at least locate the deckplate as far aft as possible. If you happen to have a large arm and stiff wrist, you may need to enlist the help of someone small and flexible for this one ;-) So while we may think that closer is better, it's not always so.

Another location to consider, is whether to install deckplates in the sole (floor) of a self draining cockpit, as on the W17. The dilemma is this. Deckplates nearly always leak a small amount so at least a little water will find its way below into an otherwise sealed compartment—but deckplates will then provide sponging access. If no deckplate is fitted, there's a good chance that the compartment will remain dry from the top, but without access you'll never really know if the case is leaking or some other seam has opened up.

In the case of my personal W17, I've chosen this solution. I've installed a 240 mm round hatch in the aft bulkhead (where I want to keep just small, light objects) but installed a larger (400 × 240) hinged hatch (with radiused corners) under the mast. Through that hatch, I can readily reach-in and remove a deckplate installed low-down on one side of the vertical bulkh'd—giving me direct access to sponge any water from that sealed area under the cockpit sole, without having an opening in the sole itself. See sketch:

Place this to port if you are right-handed—to starboard if a lefty. Deckplates are typically 4" and 6" diameter, but while 6" is often too big to install, 4" access is tight.
So I went shopping for 5" and found some at $8 each at DuckWorks (USA). They also offer the option of some with transparent lids and these are great in the amas, as you can then see if there's any water before disturbing the seal each time for no reason.

Although the one proposed in the forward bulkhead (see sketch), does not give me visual access inside the compartment, I really don't need to see, unless water is getting in. In such a case, a deckplate in the sole would not give enough access to work through anyway, so really offers little advantage here. Should I suspect a structural issue that needs work, I would just remove part of the sole (floor) anyway.

To do this, I would cut one or two rectangular holes of decent size (between the beams) and make any needed repairs. I'd then reclose them as detailed here.
Bevel the edge of the hole at about 35° with a saw or grinder. Then fit a new piece of ply with matching bevel, so that it lays 'just below flush'. Then clamp a small strip of wood under the forward and back edge of the hole, to support the primarily end-grain of the new ply. With the new ply sheathed on its underside, lay this in place with some wet CSM (chopped strand mat) or epoxy thickened with short cuttings of glass and with a sheet of wax paper over, lay a larger, temporary piece of ply over each opening and weight it down so that it cures in a flush position. Once cured, sand the closing and sheath over the top and paint. Good as new and not much heavier. I've also used the same basic system on foam composites in low-stress areas and never had a problem.

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