Sealing SeaCocks

[ebb]

elliotr, sir,
But maybe the confusion is what you DON'T have in the Cavity under the companionway.

The square opening you go thru to get inside the cabin is the (Companionway.)
The seat in the cockpit that extends across the width of the boat in front of the opening is the (Bridgedeck.)

On the floor of the cockpit in the corners of the bridgedeck and the side seats you'll find two holes
which are the cockpit drains. They are approximately 1½" in diameter.

Climb inside the cabin with a flashlight, squat down facing the back of the boat and look in under the cockpit.
(It sounds like you do not have an engine there?)

Look just inside the opening in the plywood. (Bulkhead)
Looking on either side of the curved cavity: (Bilge.)....
you should see - fairly close to the plywood bulkhead - corresponding holes, holes with thru-hulls installed in them,
or maybe fiberglass tubes, that obviously are a match for the corner openings above in the cockpit deck.
Originally these holes (thru-hulls) had short up-right fiberglass tubes connected to the hull.

Those tubes or thru-hulls, and the similar but shorter tubes underneath the cockpit drain holes
...should be connected together with hose
...as you see in the photos Bill has pointed out.

The seacocks (marine valves) in 'Bill's' photos are installed over holes in the hull that have thru-hull fittings in them.
(You posted a photograph of one on the outside of your hull, called a mushroom head thru-hull.)
This is probably a metal fitting. If you have two of these symetrically placed (across from each iother) in your bilge,
(a second mushroom head thru-hull on the other side of your hull outside)
they have been added later by a former owner.

The fiberglass tubes mentioned in the paragraph above are original installations by the Pearson factory.
These tubes have hoses directly clamped to them. Factory original installation had no seacocks, no shut-off valves.
If you do not have fiberglass tubes fiberglassed to the hull now, then someone attempted, or accomplished, an upgrade.
If you have thru-hull fittings installed on both sides of the bilge (just under the cockpit drains) and no hoses,
then the upgrade is NOT complete.
If you have thru-hulls in the bilge that are not obviously the cockpit drain system described here,
they could be for other uses.
For example, the former owner may have added one dedicated thru-hull, on the port side, for the sink drain, as an upgrade.
There may be another, probably smaller thru-hull as a salt-water source for the sink. BOTH should be protected with seacock valves.

It sounds like, from your descriptions, that there are no hoses connecting cockpit drains to the thru-hulls in the hull..
The seacock in your photo is in a position that is not familiar to me. The cut-out in the access panel, if that is what it is, and the flatness of
the hull are unfamiliar also. That seacock may not be for a cockpit drain.

There is no way around not having cockpit drains. The Pearson factory directed them conventially thru the hull underwater.
ALL parts of the cockpit drain system should be in perfect working order to ensure the boat doesn't sink.
Adding seacocks is often the modern skipper's first priority in safety upgrades. If something happens to the hose, the hole can be shut OFF!

Describe back what you see, OK?.....if you want further tips.
Photos will be extremely helpful!!!
[I apologize if any of this sounds patronizing. Trying to spread out the problem to get a look at it.]