Islander 28 thruhull fitting?

[downeast450]

I have a steel fitting with a large wing nut tightening it into the hull in the bilge. The fitting is 2+" in diameter and has a plastic insert that is secured by a pin. The inner plastic plug is made watertight by two O rings that are spaced about 1/3 of its length from each end. The outer end of this plastic insert is flush with the outside surface of the hull. If it were not facing horizontally I would suspect it of being a depth transducer face. This assembly is mounted in the bilge and is about 6" above the top of the keel. I have two spare plugs for this fitting. I am guessing it is a garboard plug. It is not at a low point in the bilge.

Can anyone tell me what this is?

Downeast450

[hellosailor]

Sounds like the plug you have with the o-rings is a dummy to be inserted when a knotmeter impeller is routinely pulled for cleaning. Found a knotmeter with no impeller wiring or impeller on the boat too?

Does not sound stock, whetever it is. Usually when there's an old hole in the boat, you either seal it up forever, or install a larger hole for some newer part that will work well there.

[downeast450]

There is a knot meter in the hull at a separate location. It is not in the bilge but on the hull aft of the keel. That sure sounds like a probable answer. I have not found another knot meter but there are two more spare plugs, both with anti fouling paint on their exterior surfaces. One has its O rings and the other one does not. That would be 3 dummies? I suppose it might have been a knot meter and was kept when for some reason another one was installed. I could use it as a garboard drain I suppose. I am not excited about having "extra" holes in the hull.

[hellosailor]

Well, if you're really serious you would have twin knotmeters, one for each tack.<G>

Does anyone really use garboard drains instead of a bilge pump these days?

[downeast450]

Some storage yards require one. I discovered that this boat's cockpit drains freeze up. If it isn't covered the cockpit could fill and spill into the cabin. If unattended a garboard drain would be nice! Bilge pump, certainly but winter storage without an opening to the hard would be risky. I must take a look at the drain configuration and either eliminate a bend in the hose or make them larger.

[Paul Comte]

Your "thru hull" in the keel stub sounds exactly like what we have in our 1979 I28.

As to the garboard plug, I wish I had gotten it installed last fall. This year we have the mast down so the boom cover isn't on the boat. My tarps, two layers, failed over the cockpit. Before I caught it the keel stub became full of water which is now frozen.
This boat is getting a plug! Next year, to be sure, I will also set some heavy bags of antifreeze jugs in the bilge, just in case of the open plug freezing over.
Three floors were already broken and coming out this spring so I'm not overly worried about the freeze up breaking them...
Paul
I28
Milwaukee, WI

[downeast450]

Is your fitting for your knotmeter?

I did dump a couple of gallons of non-toxic antifreeze into the bilge along with a bottle of citrus cleaner last fall. The sweet smelling pink liquid has remained liquid even with the frigid temperatures we have. I circulated it with my wash down pump to clean things from the engine mounting to the forward most compartment of the bilge.

I am going to add a true garboard plug, too and remove the "knotmeter"? fitting.

Downeast450