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Bottom of keel photo and question

Posted: Sat Nov 28, 2020 5:23 pm
by sjm823
bottom of keel.pdf
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I'm attaching a photo of the bottom of the keel of a PDQ 36 and wondering if this is a serious problem or just surface imperfection? Outlined in yellow is a crack running along the center of the bottom of the keel.

Re: Bottom of keel photo and question

Posted: Tue Dec 01, 2020 5:51 pm
by James Power
This looks like the joint between the 2 halves of the keel. Was there water in the keel?

James

Bottom of keel photo and question

Posted: Tue Dec 01, 2020 8:26 pm
by martincreek150
I've tried to examine the photos, and I can't seem to make out a "crack". I see what looks like barnacle "cement" and some roughness. Can you insert anything into the "crack"? Is water oozing or leaking from the "crack"?

I'm not sure where I gained this impression, but I've always thought the keels were scabbed onto the hulls. I understood the design permitted the keels to shear away from the hulls in an extreme grounding, without damaging the integrity of the hulls (sacrificial keel). I've guessed that the keels were hollow, and that water might leak into the keel if the keels "cracked". Or, maybe the keels are filled with foam? But that water entering the keels could not enter the hulls themselves.

If a keel is cracked, a fiberglass wizard should be able to make quick work of a repair. Make sure there's no water inside and then slap on the glass. So, what say the experts, are the keels sacrificial? Hollow?

Re: Bottom of keel photo and question

Posted: Fri Dec 04, 2020 7:28 pm
by James Power
Yes the keels are hollow, with no foam, and "sacrificial". If memory serves after 20 odd years, the keels were a split mold bonded together with a structural adhesive like Poly Bond and glassed over on the inside. My guess is that the crack is in the Poly Bond joint. If the keels are dry it is likely a cosmetic issue. If the keels are flooded it should be addressed. Adding glass to a keel is always a good idea, they have a hard life. The trailing edge would benefit with being more refined to aid with laminar flow. Also look at the keel to hull joint, about 10 inched down from the fillet. I have repaired a couple of these that had cracking along the length.

Hope this helps
James

Re: Bottom of keel photo and question

Posted: Sat Dec 12, 2020 1:33 pm
by catalacmarc
While our buyers survey revealed blisters in the port keel, when we next hauled we had water in the port keel as well. The starboard keel was fine, no blisters, none in the hull. The keel was drained and these were dried and repaired. But somewhere along the line someone had faired the joint down the middle of each hull with polyester compound which had ugly but superficial blisters. As the keels are basically glued on the hull, water in the keel is no great threat to the hull integrity. People have been known to install drains in the bottoms of the keels but care needs to be taken to depress them so an accidental grounding won't knock them off. Why one keel was the only major component blistered is anyone's guess.

Re: Bottom of keel photo and question

Posted: Wed Mar 17, 2021 11:16 pm
by sjm823
James Power wrote:
Fri Dec 04, 2020 7:28 pm
Yes the keels are hollow, with no foam, and "sacrificial". If memory serves after 20 odd years, the keels were a split mold bonded together with a structural adhesive like Poly Bond and glassed over on the inside. My guess is that the crack is in the Poly Bond joint. If the keels are dry it is likely a cosmetic issue. If the keels are flooded it should be addressed. Adding glass to a keel is always a good idea, they have a hard life. The trailing edge would benefit with being more refined to aid with laminar flow. Also look at the keel to hull joint, about 10 inched down from the fillet. I have repaired a couple of these that had cracking along the length.

Hope this helps
James

THANK YOU James, this is very helpful and I agree it looks like a joint "split mold bonded together" so my concerns are probably only a cosmetic issue because the bilges were dry.

Re: Bottom of keel photo and question

Posted: Tue Mar 30, 2021 5:09 pm
by James Power
Glad to help.

James

Re: Bottom of keel photo and question

Posted: Wed Mar 31, 2021 5:58 pm
by thinwater
SJM: You may not have understood James. When he suggested finding out if the keels were flooded, he did NOT mean whether they was water in the bilge, he meant "did water drain out of the keel when hauled" or did you drill a hole to find out. Because they are separate you would NOT find water in the bilge if they are flooded. You might not find any now, since they have probably drained dry (if that is a crack).