Re: Leaking P19 keel trunks -- a diagnostic approach.
Sun, 29 Aug 1999 12:16:55 EDT

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West Wight Potter Website at URL
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In a message dated Sun, 29 Aug 1999 10:49:47 AM Eastern Daylight Time, writes:

> Has anyone tried to understand why this keel trunk leaking problem confined
> to the !-19's? The P-15 also has a very loose keel situated in, what I
> believe, is a similar trunk, and yet you don't hear of this problem with the
> P-15's. I have never had a drop of water come through the trunk of my P-15.
> Not a drop. The P-15 does have a habit when beached on a gravel beach with
> chop bouncing the hull on the beach, to get gravel jammed in the keel trunk
> making dropping the keel difficult until you can work out the stones jamming
> the keel. I don't know if that happens to the daggerboard of the P-19. I
> kind of doubt it.
> What is different between the design of the 15 and the 19 trunks that allows
> this inconvenience in the 19's?
> Geoff
> P-15 Lollipop
> N. Lake Tahoe, NV

Hi Geoff,

I'm planning on rebuilding the keel trunk on our 1985 (Joe Edwards-built) P19 this winter, so I've given this topic a lot of thought. I'll hazard a guess in answer to your question by telling you a story about a modification I made to our keel trunk.

Earlier this spring, I put some extra fiberglass on the keel trunk to strengthen it and made one small oversight that was very illuminating. I forgot to drill out the original hole for locking down the keel. We got to the dock and there was no way to lock the keel down. So, before we left the dock. I got out my tool bag and juryrigged some bungee cords to hold it down.

an interesting thing happened -- the keel pumped a lot of water into the cabin. It had never leaked before. I took a look at it and noticed it was sitting about 1" further aft in the trunk than it used to. I rigged the bungies so it pulled the keel forward and the leak slowed to a half cup in a day's sailing.

If you look at an old HMS19 (and I've looked at Jerry B's a number of times), the keel trunk is much longer from front to back than the one on our boat. There is ample gap both in the front and the back of the trunk -- the massive cap on the top fits in with precision and holds the keel securely in the middle of the trunk. The old boats don't leak a single drop, even in the worst conditions, and they don't have any gaskets.

If you recall, I wrote that Joe Edwards lost or threw away the original keel trunk mold designed by Herb Stewart. Herb knew what he was doing, and that expertise was lost when the mold was lost. I'm guessing that's the difference.

With the keel located precisely where it's supposed to be, the pressure of the water being forced up into the keel trunk is dissipated evenly so it doesn't leak. On some boats, it's focused in one small area by the position of the keel and it causes leaks.

On the swing keels of the P15's, the keel is located precisely by the pivot bolt and can't get out of position.

I don't think the keel *trunk leaks*. I think it would be more precise to say that the *keel acts like a pump* water by creating temporary small areas of very high pressure and that *position of the keel* is critical to prevent it from creating permanent areas of high pressure.

Food for thought...

Judy B