Skipjack Forward Hatch Ideas?

[Mark Gudschinsky]

The owner (Laura) who commissioned the Skipjack we have on the ways in the boatshed has requested a forward hatch and has submitted some tough specifications.

The forward hatch is going to be 16

[Pipefitter]

Just a thought as to smashed fingers. Could you not put a damper on the hatch like is seen on car hatchbacks? They make them in stainless steel and with a twist lock feature using detents for easy and positive locking.

[Dave R1]

This would be a bit odd on a boat but perhaps you could work out some parallel arms that would allow the hatch to lift as it moves forward. You'd need to figure out a way to dog it closed at both the fore and aft edges but that could be done.

I could see about making a sketch to work out the geometry if it would help.

[Pipefitter]

Try a little builder salesmanship..."if we use a hinged hatch,when it is open you can lay back against it like a chaise lounge whilst you tan."

[Barry Pyeatt]

If I recall correctly, isn't the captain having a small cuddy cabin added onto her open Skipjack? Foredeck space seems as though it would be quite limited as well as cabin top space. Verry difficult to make a sealing hatch that slides. After all you are asking a tight fitting piece (the top) to slide off of a framed opening. Friction alone makes that problematic to say the least. Not impossible, just extremely difficult. And if it is to seal tightly (watertight) it will have to fit extremely tight. Much more difficult to make it move in either direction Unless it lifts and then slides to open. And slides and drops down to close. But it would require some cam type latches to hold it down once it dropped onto the frame.

Dave's suggestion of a pair of parallel arms could allow for the lift needed and then swing forward, but I'm not sure that the geometry is going to allow it go clear completely without making it quite complicated. Perhaps a parallel set to lift and them attached to a pair of sldes to move fore and aft.

The actual seals to make it water tight could be simple door stop beads set into the frame so that when the top dropped over them they would compress to seal it.

Alterrnately, the beads could be on the bottom edge of the hatch and compress against the deck or surround of the frame to seal. But this is not as good as having the hatch drop onto a sealing bead.

With a lifting hatch the seal is a lot easier to make and keep working after repeated cycles of opening and closing. Since the hatch would simply be lifting off of the sealing bead and not dragging along it as with a sliding hatch.

There are some good adjustable tension, "easy lift" locking hatch supports available thru Duckworks and a few other suppliers. No Squished fingers with them unless you press down on them really hard with your finger under them. They are quite tough and hide out of sight beneath the hatch.

I apprecitate the low profile desire, makes laying out on the foredeck a lot more comfy to get a suntan. The low profile isn't impossible, just weaker since it has less of a curve to it to add strength.

[PAR]

It's possible to have a flush hatch, but will have to hinge and water channel with drains. A sliding hatch is a slow leak. The only sliding hatches I've seen that don't leak have a "garage" in front of them and a double sloped track, to permit the hatch to squish some gasket material when closed. I've never seen a slider without the garage that didn't leak when a bucket of water was tossed (picture a boarding wave coming over the bow) at one of it's corners.

To keep the slider low profile, you should think about metal tracks on the underside of the hatch that mirror similar on the hatch opening carlins. It'll still leak, but not too bad if you keep green water off the deck. HDPE makes excellent slides and tracks. An interlocking "U" or "L" shape is commonly employed for the track and slides. Pins in slots and other contrivances have been used, but generally simpler is better in these types of things.

Make it strong enough to stand on. You'll not understand this until the boat pitches, while you're on the foredeck and you have to stand on it or go for a swim.