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Discussion Starter #1
Hello,
I recently purchased a 1976 compac 16' and would like to know what the material is used for keel ballast. I drilled a couple of 1/4" holes in the bottom of the keel and water came out ao I am assuming that the keel material will have to be removed and replaced with.... what? Any and all advice is greatly appreciated.
 

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Compac themselves are still around and I expect would be willing to help. I thought they were concrete ballast.

How do you expect the water got inside? Obviously, something got you to drill the holes.
 

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I beleive they have encapsulated concrete ballast. But, emailing the manufacturer is a good idea.
 

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Discussion Starter #4
When I got the boat there was standing water on top of the keel with numerous cracks in the stuff ( FG?) covering the ballast so basically it had to leak... I drilled a couple of inspection holes and water weeped out.
 

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If it was mine, I would just drill a few more holes, let it dry for a couple of months, and seal it up. Maybe see if you could get epoxy to flow through from the top. Then plug the holes on the bottom, and fill the void with epoxy. Again, this is just me. There is probably a better way to do this.
 

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When I got the boat there was standing water on top of the keel with numerous cracks in the stuff ( FG?) covering the ballast so basically it had to leak... I drilled a couple of inspection holes and water weeped out.
Sounds like some fairly serious structural issues (cracks through the glass). Be sure you know the right thing to do to remain safe. It stands to reason that the ballast has delaminated from its encapsulation. It doesn't sound like a band aid job to me.
 

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Discussion Starter #8
Sounds like some fairly serious structural issues (cracks through the glass). Be sure you know the right thing to do to remain safe. It stands to reason that the ballast has delaminated from its encapsulation. It doesn't sound like a band aid job to me.
Thanks man. I've done a fair amount of fiberglass work on older boats but nothing like this. I don't intend for it to be easy. I'm going to remove the concrete ballast with a chip hammer. Check the encapsulation, possibly recoat, relaminate the keel cavity. Then, I just ordered 300lbs of lead ingots off of ebay so I'm going all in. I've read great reviews/advice on using lead as compared to other materials such as concrete. There's some great total Compac restorations on youtube.
 

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Interesting job. Are you going to remove the bilge to access the ballast or go through the encapsulation from the outside. The bilge would leave an intact encapsulation to refill, but then you need to structurally replace the bilge. The encapsulation probably needs to be reinforced, but more curious is how you insure a good bond to the encapsulation, when you refill.

The lead will change the weight of the ballast, but I doubt that will make sailing her all that different. If significant, it may alter her waterline though. Is your plan to imbed the ingot into an epoxy slurry of some kind? Insuring this slurry bonds to the existing glass?
 

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Cool idea with the lead. It should sit lower in the keel and make the boat stiffer. It will be less dense so you will have some void space to fill. You might want to consider the weight of the filler too. Those compac 16s are already pretty heavy boats, so I wouldn't want to over do it.
 

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Discussion Starter #11 (Edited)
Interesting job. Are you going to remove the bilge to access the ballast or go through the encapsulation from the outside. The bilge would leave an intact encapsulation to refill, but then you need to structurally replace the bilge. The encapsulation probably needs to be reinforced, but more curious is how you insure a good bond to the encapsulation, when you refill.

The lead will change the weight of the ballast, but I doubt that will make sailing her all that different. If significant, it may alter her waterline though. Is your plan to imbed the ingot into an epoxy slurry of some kind? Insuring this slurry bonds to the existing glass?
yes I will use some type of epoxy slurry. I am going to pop the cap to get access to the encap.
 

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The ingots may or mayn't fit together well. I made up a mould of 2" angle irons welded with flat bar strip for ends. they fit together well one row up to next row down. Length could be how wide the cavityy is. after lots of strengthening glass. Fill with slow kicking resin. Same weight as concrete but lower down is good.
 

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Seems to be a lot of work that may be unnessary Maybe a bit of tear off in the bilge and decide if a good layer of glass will do while the water. drips out below.
 

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Discussion Starter #14
Seems to be a lot of work that may be unnessary Maybe a bit of tear off in the bilge and decide if a good layer of glass will do while the water. drips out below.

Well, I've decided on the lead. According to the reaearch I have done you get a lot more bang for the buck if you use lead. Also I want to make sure it good and dry so the top is getting popped and the concrete taken out. I want a total restoration and not be worrying about a keel being half repaired, or anything else for that matter.
 

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Discussion Starter #15
The ingots may or mayn't fit together well. I made up a mould of 2" angle irons welded with flat bar strip for ends. they fit together well one row up to next row down. Length could be how wide the cavityy is. after lots of strengthening glass. Fill with slow kicking resin. Same weight as concrete but lower down is good.
I've seen on other sites and the net where people have good luck cutting lead with a course, carbide tipped skil saw, miter saw, table saw, etc. So I can always cut an ingot into filler pieces and then slurry it in.... I hope...lol. You know concrete ballast just sounds like a bad idea, esp since the top of the ballast is the lowest point in the hull making it an ideal little reservoir for any intruding water. I thank god I'm in florida and don't have any freezes to worry about or good bye keel I would think. This may sound dumb but why the "strengthening glass"? If you lay and fill around the ingots and then slurry it, that should suffice, no?
 

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One advantage of concrete is absolute symmetry in weight distribution. When you place the ingots, you're going to need to distribute them very evenly and intently.
 

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Discussion Starter #17
One advantage of concrete is absolute symmetry in weight distribution. When you place the ingots, you're going to need to distribute them very evenly and intently.
Good piece of advice, I'll try to send in pics as I go along. I appreciate all your concern and good points/advice.
 

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Talk to ComPac (Hutchins Boat Works). They replaced my stainless steel center board trunk with a new fiberglass one for around $1400. I have a 2002 SunCat. Great people to work with.



Sent from my SM-N950U using Tapatalk
 

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I've seen on other sites and the net where people have good luck cutting lead with a course, carbide tipped skil saw, miter saw, table saw, etc. So I can always cut an ingot into filler pieces and then slurry it in.... I hope...lol. You know concrete ballast just sounds like a bad idea, esp since the top of the ballast is the lowest point in the hull making it an ideal little reservoir for any intruding water. I thank god I'm in florida and don't have any freezes to worry about or good bye keel I would think. This may sound dumb but why the "strengthening glass"? If you lay and fill around the ingots and then slurry it, that should suffice, no?
No, Laying and filling around the ingots and then slurrying over it is not a complete solution. (By slurry I assume that you are suggesting using a slightly thickened polyester resin since anything thicker than cough syrup won't flow into voids and anything thinner will crack simply from the heat of the thermosetting process and will shrink away from the encapsulation membrane failing to make a bond.)

By way of an explanation of why a minimally structural membrane is needed above the ballast, the bonding of the ballast keel to the encapsulation envelope is a key structural component in the strength of the keel and hull above. The ballast serves as the 'web' of an 'I' Beam allowing the fiberglass on either side to act and flanges. When the bond is intact, this is a very stiff structure that concentrates a lot of the stresses into a very small area where the keel turns down into the encapsulation envelope both fore and aft and side to side. Over time these stress risers take a toll on the strength of the laminate in those area weakening these critical areas in the boat. Adding to that is that boats like the Compac are often trailered with with the keel resting on the trailer and supporting the weight of the boat. The bumps in the road will result in numerous repetative small impacts to the critical laminate in the area where the keel turns down into the encapsulation envelope, further taking a toll on the strength of the laminate in this area.

While popular mythology suggests that the majority of cases where keels are lost are the result of keel bolt failure, in reality, an extremely large number of cases occur due to a failure of the laminate both fore and aft and side to side of the actual keel connections. In that regard, the current fledgling studies of keel losses show that its not just bolt on keels that are being lost.

Beyond that, in a hard grounding, the ballast keel is pushed upward against the weakened laminate and the bond between the ballast keel and encapsulation envelope is stressed and breached by the deflection of the skins of the encapsulation envelope. If the encapsulation envelop is pierced by the grounding, the boat is likely to minimally potentially be un-repairable and more extremely sink. A structural membrane, ideally coupled with transverse framing, reduces the stresses on the ballast to hull bond and on the laminate at the turn-down into the encapsulation envelope providing a much higher probability of surviving a hard grounding with a repairable boat.

If you are going through such an extreme effort to improve an otherwise intact and adequately constructed boat, then it would seem that installing a structural membrane above the ballast would be a pretty cheap bit of insurance that no matter how long you own the boat, almost no matter how you abuse the boat, and no matter where you trailer it, the repair will remain solid.

Jeff
 
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I owned a late 70s Com Pac 16 and when I got it it had suffered a grounding at the leading edge of the keel and the glass encasement at the bottom had split from the forward edge down the port side at the turn about 2/3rds of the way aft. The ballast was solid lead and was exposed, obviously. I repaired it by first cutting back and dressing up the ragged edges of the keel encasement, then used a tube of West Marine self-mixing Six10, the caulking tube stuff, which I injected between the lead keel and the fiberglass encasement, all along the bottom. I then used a floor jack with a 2x4 on it so it applied pressure the full length of the bottom of the keel and sandwiched the encasement up against the lead keel. Six10 was forced out as it the space between the keel and encasement was closed up. I spread the excess that squirted out along the gap to fill in the edge that I'd cut back and dressed up. Once the epoxy had cured I sanded the edge smooth and roughed up the encasement up several inches along the leading edge, bottom, and port side of the keel, before applying fiberglass woven roving wetted out with epoxy. Once cured I fared the keel repair using an orbital sander. Then I used plain old white spray paint to finish it up. Looked pretty good and never had any further problems with any delamination or any other issues. The boat had been on the hard for a while before doing this and so the keel was fully dry before I effected the repair.
 
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