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Lead 'boot' - yes/no?

4K views 24 replies 13 participants last post by  SlowButSteady 
#1 ·
One additional question and then I will go in a corner and think!

I am 'considering' adding a lead 'boot' to the bottom of my fin keel; this would serve as a sacrificial element protecting my fiberglass keel with internal balast and would provide additional righting moment that would help 'stand up' the boat. I am looking at an additional 500# on a 12000# sailboat with a current ballast of 4000#.

I have, however, read that standing a boat up with additional balast is a good thing in strong winds, it is detrimental to the performance in light winds. I'm confused - I thought that standing up a sailboat was a good idea. Good/bad - Yes/No - Why?
 
#2 ·
I would guess it would depend if you need it or not, My boat came with A-4 cast iron motor & I have changed it to YMS 8 aluminum motor, so I am light in rear & need to load more to the back to keep my water line flat & mast rake right. How did you plan to add this ballast boot to your boat?..Dale
 
#3 · (Edited)
Adding weight to the bottom of the keel will give you the greatest righting moment for a given weight. However, the weight will also lower your boat (i.e., raise the waterline) that much more, thus increasing the wetted surface area. As the hull moves through the water the relative contributions of wetted surface area (i.e., skin friction) and induced turbulence (i.e., form drag) change with increased speed. At low speed wetted surface area is the largest component of total drag, while at high speed turbulence increases dramatically and becomes the largest component of drag. So, by increasing the weight at the bottom of the keel you'll be increasing drag at slow speeds because you will have increased wetted surface area. But, at higher speeds the boat will heel slightly less, thus probably producing less turbulence, and be have slightly less drag (as long as you haven't added so much weight that the bottom of the transom is underwater, thus producing even more drag).

The best bet is usually to stick to the designed displacement of the hull. The designer probably put a lot of thought and effort into figuring out how much ballast was needed. Most folks (yours truly included) have more than compensated for any weight savings by accumulating all manner of junk on their boats. IF you have removed the engine, or replaced it with a much lighter one (or saved a significant amount of weight on the boat in some other fashion), THEN compensating for the difference MIGHT be appropriate. Otherwise, I would just leave it be and save your money for new sails, or somesuch.

All that being said, I used to own a boat, the Victory 21, that was built with an optional bulb on the bottom of the keel (mine had the bulb). The consensus was that V21s with the bulb were better sailers than those without. A V21 is a pretty light, pretty narrow, boat either way. My guess is that in light air the boats without a bulb would have had the edge. However, I sailed my on SF Bay, where the extra righting moment was often much desired.
 
#7 · (Edited)
So you would then have a presumably watertight keel with several holes drilled through it? Even if it did nothing else, a hard grounding is likely to jiggle those bolts enough to let water penetrate into the keel (if they weren't leaking already). Like I said, it's probably best to assume the designer knew what he was doing in the first place, and avoid hard groundings. A good depth sounder must be a small fraction of the cost of this keel project you're contemplating.
 
#5 ·
I am 'considering' adding a lead 'boot' to the bottom of my fin keel;
Ok :D who doesn't like the boat "tipping"? Hmmmm? It took 2 season for me to get used to it myself. :cool:

How does one go about making and attaching a "boot" to a keel?

Jus wonnering....
 
#17 · (Edited)
Ok :D who doesn't like the boat "tipping"? Hmmmm? It took 2 season for me to get used to it myself. :cool:
It took me 2 seasons to learn that having the lee rail 6 inches under wasn't fast. :D I preferred beating with a large heel angle from the first day I went sailing - it was (and is) better than any arcade ride I was ever on.
 
#6 · (Edited)
what boat are you considering adding this to? just saying it seems a lot of effort/cost (virgin lead?)/engineering for integrity etc to justify... just get a new boat...

if you stick with the idea maybe consider the bulb keel as an addition that may be a wee bit more already proven by current designs.

Only wondering if you are making a purse out of a sows ear....
good luck

oh... you could always buy a cat :eek:


hate to say, but this just sounds wonky... seems trollish, but I may be off base as you have posted more than twice. In any case, I wish you the best with your home brew C shaped lead keel add on project
 
#10 ·
micheck: If you want to "stand up the boat", have you made sure your sails are in proper shape and that you are good at knowing when to reef? Sails that are stretched out--not necessarily obvious to the casual observer--will make it more difficult to go to weather and have you heeling more than necessary.

It might be worth the effort to check your speed made good (with a GPS) before and after reefing. You may discover that you have not reefed as soon as you might. In our case, my better half will remind me that we aren't going any faster at a heel angle of 20 degrees than we would at 15 degrees with a reef in. BTW, my boat is in the 12000 lb displacement category as well.
 
#14 ·
OK - the wisdom has spoken ...
Well, a bunch of duffers with nothing else to do have spoken. But, I think you made the right decision.
 
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#13 ·
I think you SHOULD put the lead boot on the keel?

Why?

That way when every sailor who ever walks by your boat ask's you "WTF is that?" You can answer, "It is DAS BOOT!"

Other than the above, I see no upside. :D

MedSailor
 
#15 ·
If your boat is initially tender adding 50lbs. to the keel will not help much. Your increase in displ and your new waterplane will help some and you will see an increase in stability once you hit about 20 degrees of heel. What is the current draft of the boat? If we knew what kind of boat you had it would help.
 
#16 ·
500 lbs at the bottom of the keel (vs. 500 lb wine cellar in the bilge:D) would help a fair amount with ultimate stability, no?

If it is also intended as a reef-feeler appendage, it would be more useful if it extended up the leading edge of the keel a bit. Maybe a bit of 5200 to keep from having to drill through an encapsulated keel? (kidding of course)
 
#22 ·
Since these guys are cutting off part of the keel, in preparation to adding a bulb, the resultant is likely to provide less lift. Remember, the keel of the boat provides both a righting moment and fluid dynamic lift, with the latter giving the boat its pointing ability. Reduce the foil by 15 or 20 percent, an you are likely to reduce the lift provided by the keel by 15 or 20 percent. Sure, the boat might have a similar, or even greater, righting moment as it did before the "surgery". however, it's also likely to loose some pointing ability unless the keel is somehow further modified (which is probably much more difficult).
 
#21 · (Edited)
No matter what you decide, the execution is paramount.

I have sailed for 4 years on an '85 C & C 32, originally built with the standard fin keel. One of the two previous owners reduced the draft to the designed optional centerboard draft and installed a bulb. Not sure, but it may have been installed at the yard I worked at in the '80s. While the bulb dealt with the draft target there were two negative changes -

1) the boat exhibits considerable weatherhelm upwind with winds over about 12-15 knots resulting in difficult steering, regardless of any tuning changes, although reefing the main does help. We have shifted weight, filled tanks, emptied tanks, with little result. When we are heading upwind we try to cram as much crew weight as possible aft. The conclusion is that when the draft was reduced water flow to the rudder changed. When observing the same model with factory installed centerboard the keel profile runs further aft. The rudder is the same on each option. Of course, none of us are engineers or designers and the only advise we are getting is 'buy a new keel'. The Mars website has great and thorough installation instructions, that definitely should be followed. In the long run this installation is questionable and my feeling is (from working in a number of yards for 22 years) that the bulb installation was likely a yard manager stepping back and telling the staff "ok, put it there" (yes that does happen).

2) the owner now has an anomoly and will eventually be looking for a buyer that wants this arrangement or does not have a clue about it's uniqueness. Regardless, the resale value is likely tarnished compared to others that are as originally built.

So, my advise is think twice about what you are considering, get thorough professional advice, weigh the immediate and future costs. Your original question was about protecting your encapsulated ballast. The reality is everybody runs aground sooner or later, often because we are not always where we think we are. Hopefully your boat was built tough enough to withstand the occassional bump or grounding, depending on the bottom material of course, and the big risk is mostly cosmetic. ;)
 
#24 · (Edited)
I like my cutaway forefoot keel on my old '66 C-29 Columbia more every day...My girl's 2 to 1 disp.to ballast ratio makes up for alot of what she don't have in room (8' beam) and speed (6.36 kts) but at least I know if I get slapped down by an errant T-storm outflow with canvas up that I am probably going to bounce back into the game...and for the record..I would say add the lead...might be a bit more ungainly in performance possibly as it is not factored into the original architect's design but it probably gets her back on her feet more quickly in a knockdown at least..that's my take but differnt strokes for differnt folks...I'm a coastal cruiser..a racer may tell you something else..
 
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