Centerboard casing - DS2

[Mackrelman]

I have a 1973 DS2. I have jammed the centerboard in it's casing a few times with shells etc and have always been able to shake it out with the lines. However it's only a matter of time till it gets seriously jammed at the wrong time.
I have seen pictures of (2) DS's that had a drain plug on the top of the cboard trunk where I thought a stick or whatever could be used to force the board down.
When I tried drilling a pilot hole for a drain plug assembly today (6" aft of the centerboard jam cleat) I went thru one layer of fiberglass , past a void (maybe an inch deep, and then hit another layer of fiberglass. I stopped at that point.
Does anybody know the actual construction of the centerboard trunk?
Thanks for all info,
Mackrelman

[GreenLake]

Does it look like cockpit molding forms a "hat" over the trunk, or is there a visible seal around the CB trunk at the level of the cockpit sole? The air gap that you report make it sound like you have the "hat" or nesting trunk design. I think that's what I've seen when I sailed on a friend's DSII from that vintage, but I've seen from contributions here that there are some double-hulled DSs that simply have a hole in the cockpit floor for the CB trunk to poke through. Those may be later models.

The main problem with the double trunk is that water in the CB is under high pressure under way. If you don't seal the hole in the actual trunk, you will have water squirt into the bilge. Making the hole a bit wider and glassing in a bit of pipe would solve that. You might need a plug for the pipe to keep water from squirting into the cockpit.



Often, the jammed CB trunk happens after a beaching, so careening your boat is an option at that point. However, you've drilled your hole, so you'll need to figure out how to make it water tight.

[Mackrelman]

Thanks for the input.
One of the reasons I love my DS2 is the compartmentation. She's esentially double hulled and I think that's what is going on here.I do not want to comprimise that
I have the saddle configured centerboard trunk.
I thought about continuing the project and putting a tube in but maybe the risks are not warranted
Since the 1/4" pilot hole I drilled only went thru the top layer of the trunk (I stopped when I hit the lower obstruction) all I have to do is temporary plug the hole
and I'm back to normal but have not solved the problem
I want to think this thru carefully before epoxying the hole.
My guess is that the boats I saw with "poke" holes in the CBoard trunk were not double hulled like this one.
Think I'll go sailing while I think on this

[GreenLake]

The "poke" hole is primarily an issue for boats that use lines to control the CB. I've not done a side-by-side comparison, but I would expect that it's easier to deal with an obstructed CB with a handle.

The CB lines also cross that same gap between CB trunk and the second hull, and many users have reported leaks into the bilge from that area. So, yes, there's a some risk.

However, I think it should be possible to get this set up so that it solves a problem instead of adding one.

There are essentially two approaches:

• the first would be to overdrill the holes and epoxy a bit of pipe connecting the two moldings. With the inner diameter of the pipe pretty narrow, just enough to poke with your favorite instrument. For the pipe you would need to use something that has good adhesion to epoxy.
• the other would be to drill your top hole to the required diameter, and then to squeeze some thickened epoxy into the the gap. After that hardens, you can then drill it out to the final dimension.

Both of these work best if the gap is narrow. Depending on the geometry, the second one may result in a stronger bond between the two layers, which is important if there was any flexibility for the CB trunk to wiggle inside the cover. You'd want to make the connection strong enough that it doesn't come undone over time. But I think it should be possible to get it done.

[Mackrelman]

I have lines operating the cboard and the setup has not given me any problems other than watching the hole where one cable penetrates the hull. I wrap that with packing regularly and treat it as a packing gland , no big deal.
I like your thoughts and am considering another option. If I drill both holes to the required size for a 1/2" pipe tap and then oversize the top hole I should be able to tap out the lower hole for 1/2" NPT. Then screw a threaded tube (with epoxy or glue) into the lower hole. After the glue sets, epoxy around the top joint to seal it. It gets a bit tricky because I want a minimum of a 3/8" diameter rod
I don't think rigid fiberglass tubing exists so I'm stuck with heavy PVC
If necessary welding a hex rod onto a tap for light duty is not a big deal
Got to think about this for a while before proceeding
By the way your initial comment about water pressure in the centerboard casing is something I never considered. After I put new good quality washers on the cboard pivot pin I've had no leakage that I know of.
Thanks, JW

[GreenLake]

I think you are onto something with your tapped pipe.

When I sailed on my friend's DSII, we had winds to push us well to hull speed. There was a constant jet of water coming out of the uphaul line, indicating the pressure inside the CB. You have sealed that which reduces your water flow into the cuddy, but also means that the internal pressure is not relieved, of course.

The CB pivot sits low enough that it can leak even if the boat just sits in the water, if it's one that actually goes through the side of the trunk. Some models instead have a recess in the hull that's blocked with retaining plates. That design, of course, is leak proof.

Good luck and let us know how things turn out.