keel weight?

mr geets

Petty Officer 3rd Class
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Got into a conversation about boats and the stability of a sailboat came up. Naturally the "keel" came up and the next question was "so what does a keel weigh?"

Is there any ratio of length/weight/draft/sail area/beam or whatever that might give a weight? Or just how about how much weight would a keel weigh on a 35 foot sailboat?

Probably like "how much is a bag of groceries" but just asking.
 

Ned L

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Sep 17, 2008
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Re: keel weight?

Yep, you have it about right with the bag of groceries. More specifically it would be need to be just enough, yet not too much. lol

It has to do with MUCH more than just the length of the boat. Beam, draft, hull form, rig type (aspect ratio), intended use, construction type, are just a few of the other variables that factor into the weight and where you put it.
 

SolingSailor

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Dec 24, 2009
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Re: keel weight?

The ratio "ballast/displacement" is often used. Most cruising boats have about 30-40%, so a 35 foot cruiser weighing say 15000 pounds total, may have a 5000 lb. keel. This will vary by design of course; a high performance racer may have a larger b/d ratio to give more stability, which will allow more sail area.
 

mr geets

Petty Officer 3rd Class
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Nov 16, 2012
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Re: keel weight?

The ratio "ballast/displacement" is often used. Most cruising boats have about 30-40%, so a 35 foot cruiser weighing say 15000 pounds total, may have a 5000 lb. keel. This will vary by design of course; a high performance racer may have a larger b/d ratio to give more stability, which will allow more sail area.

Thank you. This gives a sense of weight I was looking for. Interesting the other day I was in Vancouver BC. where a guy was finish painting the keel of a sailboat while another guy looked on. (looked like the owner?). Neither of them could tell me an answer to the question and looked a bit sheepish :)
 

Artwerke

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May 22, 2013
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Re: keel weight?

My 38' Irwin has 6000 lb of lead in the keel, for an idea.
 

chris.olson

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Mar 15, 2009
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Re: keel weight?

Thank you. This gives a sense of weight I was looking for. Interesting the other day I was in Vancouver BC. where a guy was finish painting the keel of a sailboat while another guy looked on. (looked like the owner?). Neither of them could tell me an answer to the question and looked a bit sheepish :)

The keel on a sailboat, contrary to popular belief, does not necessarily provide the boat with its righting moment. The ballast does that. The ballast can be in the keel, but some sailboats like the Hunter 22, for instance, have lead ballast in the bilge under cabin sole and the keel is neutral buoyancy.

The purpose of the keel is to act as an underwater foil that counters the heeling force imposed by the sail and mast on the deck. When sailing on a reach the wind attempts to cause the boat to move sideways in the water and if the wind is strong, knock the boat down. The keel creates "lift" and provides force in the opposite direction on the hull's center of rotation. So, using the example of the Hunter H22 I mentioned above, the boat has 1,300 lbs of ballast but the keel only weighs 65 lbs off the boat and it extends 5 feet below the waterline.
 

Jim Cash

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Re: keel weight?

My Catalina 250 wing keel has 1040 lbs in the keel but that does not address the total ballast weight below the water line. Its total weight is 3800 lbs so ballast must total at least 1/3rd of this boats weight. Chief
 

chris.olson

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Re: keel weight?

Comparing sailboats is interesting.

Where the ballast is placed makes a huge difference. The Catalina 250 mentioned above has 1040 lbs in the bottom of the keel and it is ballasted at 25% (displacement 4200 lbs) with a LWL of 21.25'. If I remember correctly the Cat 25 is water ballasted? But the ballast is a long ways below the center of rotation of the hull.

If you look at a Hunter H22 (I'm restoring one right now in my shop), it weighs 2600 lbs and it has 1200 lbs of ballast that is in the bottom of the bilge with a LWL of 18.33'. So it is ballasted at 46%. This would indicate an excessively stiff boat. But because the ballast in the H22 is closer to the centerline of rotation of the hull it is a moderately tender boat that heels easily at first then "locks in" at about 25-30 deg heel carrying a lot of sail, and increasing the wetted hull length. Increasing the wetted hull length (or LWL) on a sailboat makes it faster (gives it a higher hull speed).

So combining all the factors of being able to increase the wetted hull length with heel, lighter weight, higher SA/displacement ratio, narrower beam, and being able to carry more sail without over-canvassing in higher winds makes a sailboat faster.

Edit Note:
The design of the keel can determine how well she'll point to weather too. Most wing keel boats that I've sailed, the keel tends to slip in lighter winds and it takes a little speed to get the keel to "grab" so she'll point. Typically, the better she points the faster she'll be sailing to weather. Most racing boats can point at 30 degrees. Cruisers will typically be more in the range of 45-50 degrees.
 
Last edited:

Jim Cash

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Re: keel weight?

Chris: I think you are low on percentage as the 25% is just the keel weight. Retractable keels tend to slip more than wing keels and have not noticed any real problem with that. Why didn't you also say that they are fast for their size and point higher than like kind, size, boats? The rudder size is the greater limiting factor for pointing upwind, not the keel on these boats. Chief
 

chris.olson

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Re: keel weight?

Chris: I think you are low on percentage as the 25% is just the keel weight. Retractable keels tend to slip more than wing keels and have not noticed any real problem with that. Why didn't you also say that they are fast for their size and point higher than like kind, size, boats? The rudder size is the greater limiting factor for pointing upwind, not the keel on these boats. Chief

Hi - you can look up the design data on just about any sailboat ever built on sailboatdata.com. I don't think I agree that the rudder is the greater limiting factor for how well a boat points. Granted - if the boat is heeling excessively so you can't keep the rudder in the water then she'll round up and you'll get rudder again. But chances are, the boat is over-canvassed at that point. So it's into an area where it's not the boat, it's the captain's experience level that is limiting her pointing ability.

Every boat sails a bit different - even sometimes comparing two otherwise identical boats. The tune of the standing rigging, how much mast rake you have affecting weather or lee helm, etc. are all factors that determine pointing ability besides the design of the hull and keel and how much sail she can carry. So you are correct with your statement that I should've said "fast for their size" etc because in general terms boats with a longer LWL are faster than shorter ones. I think what I was trying to say is that, if the captain has enough experience he/she can use the "trick" of increasing the wetted hull length of a more lightly ballasted boat with heel to get more speed from her.

Sailing is an art, not a science. And for my wife and I that's what makes it so fun as compared to powerboating, which we consider to be pretty boring. For powerboaters, plowing into heavy seas is an exercise in punishment. For sailors on a close haul beating to weather with waves crashing over the bow and dodger it just don't any better.
 

Jim Cash

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Re: keel weight?

Chris: Read what I said again. I was not making a general statement with regard to equal size boats having limitations pointing: only my observation regarding the Catalina 250 wing keels rudder hampering its upwind point. I respect the fact that you are an accomplished sailor, as am I!

Chief
 

chris.olson

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Re: keel weight?

only my observation regarding the Catalina 250 wing keels rudder hampering its upwind point.

Ah, sorry about that - I took it as a general statement instead of being specific to the Cat 250. My wife and I sailed a Catalina 25 many years back with the new owners onboard (new to sailing) to deliver her to her new home port in Kenosha. The Cat 25 was a pretty stiff boat and it was a Frank Butler design. But overall I was impressed with it for being a nice stable boat, but not impressed with her speed. Her light wind performance was pretty dismal in my opinion.

When they went to the Cat 250 with the wing keel and centerboard it seems to me that some of those were water ballasted and some had lead ballast. Never got a chance to sail one of those but I suspect they are a little more tender than the old Cat 25 - and probably faster. Just out of curiosity, what about the rudder on the Cat 250 limits her pointing ability? Too much heel and the rudder looses its bite and she rounds up?
 

Jim Cash

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Re: keel weight?

Chris: Can't speak with regard to Cat 25s but having raced against a cat 250 wing with a Clipper Marine 26 I know they are fast. Broadside it could run faster than the clipper. Up wind it could not point like that fine bow Clipper! The 250 was offered in wing or water ballast retractable keel. Cat 250 appears to get her speed from her flat, broad stern as her bow does not show fast. Wing keel,tall mast runs about 6.3 knots full hull speed. Now, the rudder first off is retractable and that is not to my liking. I will fix that! 13" front to back does not seem to provide enough bite compared to my Clippers huge keel. I may extend the rudder to 16" front to back below the outboard prop but not sure yet. The tall mast, wing keels are more tender but as you pointed out earlier: I think its the Skippers! Know when to reef,double reef, spill the wind if necessary! These guys have furling sails and their having problems with too much wind! As you know, out for a day ride is vastly different than sailing a vessel! Chief
 

chris.olson

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Re: keel weight?

These guys have furling sails and their having problems with too much wind! As you know, out for a day ride is vastly different than sailing a vessel! Chief

That makes me chuckle a bit. Lots of folks are using roller furled jibs these days and think that roller furler takes the place of a storm jib. And I saw one fellow not too long ago sailing a masthead sloop that was using a boom roller to "reef" his main. I noticed he had no slab reefing cringles in the main and I asked him what he does about outhaul with the main reefed down with that roller furler. He just looked at me with a blank look - didn't have a single clue what I was talking about.

That's really interesting about your rudder. I have never heard that before but you evidently have a beaching rudder and I wonder if the hold down system on it is working properly? Have you checked the hold down system to make sure the rudder is not raking aft under sail?
 

mr geets

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Re: keel weight?

I just gotta say that this has been a real education1 Thanks to all and I hope those two guys at Granville Island in Vancouver BC read and heed when someone asks about keels.
 

chris.olson

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Re: keel weight?

Very educational to me too. I learned that Jim Cash's Catalina 250 exhibits such severe weather helm close hauled that the rudder can't keep her from rounding up. That's the first time I've ever heard of a production sailboat being that far out of balance. I don't really know any other owners of Catalina 250's to ask about this. There's a couple Catalina 25's more local to us - but those are a different animal and they definitely don't have that characteristic.

The tendency for a sailboat to have extreme weather helm (and possibly even broach) is indicative of inadequate keel performance (NOT the rudder). And that's what's interesting to me. For the folks that are interested in keel design, and what the keel does for the boat, Ted Brewer (one of the top yacht designers of all time in the US) wrote an article for Good Old Boat magazine over 10 years ago that addresses keel design. Fortunately that article Ted wrote is available online:
Good Old Boat - Keel design: What's best? article
 

chris.olson

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Re: keel weight?

Folks, I called a good friend (about another issue) who is much more familiar with Catalina Yachts than I am. I happened to think about this thread when talking to him and found out that Catalina has gone thru three revisions to the 250 and that pretty much all of them exhibit excessive weather helm. He suggested that if a 250 exhibits the problem to the extent that you run out of rudder before she'll point at 45 deg to have a professional rigger tune her rigging because something is out of adjustment.

Weather helm is generally considered desirable (although I prefer a neutral helm) because if you get into trouble you can just let go of helm and she'll stand up. But it is not so desirable if it's to the point where the rudder can't steer her.

It was a point of interest to me because I had never heard of a production sailing yacht that was designed to be that far out of balance, especially a yacht as popular as the Catalina's. But I guess Catalina purposely designed them that way to be very forgiving and almost impossible to accidentally get a knockdown if the boat is over-canvassed. They made it so she runs out of rudder before you can get into serious trouble with it. Thanks, Chief, for pointing that out. Learn something new every day.
 

chris.olson

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Re: keel weight?

More on keels for the folks interested in this aspect of sailboats:
Here's a photo of our Hunter yacht that we keep on Lake Superior:

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I have the boat in my shop this winter for new paint and refits to electrical and navigation electronics. You can see the keel under there. This boat has a swing keel so she draws 2 feet of water with the keel up and 5 feet with the keel down. But the keel is neutral buoyancy and it only weighs 65 lbs. The boat is very heavily ballasted (47% of displacement) with cast lead ballast under the cabin sole. The ballast weighs 1300 lbs.

With the keel up she can be sailed in light winds but she slips to leeward pretty bad if the wind picks up much above 7 kts and she'll barely sail to weather close hauled clawing her way ahead at about 1 kt. With the way I have the standing rigging tuned, drop the keel, she locks right in and she'll point at just about 40 degrees with a neutral helm and go 7 kts thru the water. This boat is the best example of what the keel does for a sailboat.

So for the OP's original question on how much does the keel weigh? The keel can weigh almost nothing. It is merely a foil or "wing" that counteracts the thrust of the sails. The ballast CAN be in the keel, but it doesn't have to be. The keel makes the boat point and keeps it from slipping sideways thru the water. The ballast provides the righting moment on the hull. Where the ballast is placed, and how much is used, determines how the boat attempts to right itself when it is knocked down (sails touching the water) or rolled completely inverted.

This is where sailboats differ from powerboats in design - a sailboat can be rolled completely inverted in heavy seas and the wave and wind action will place the ballast off the center of rotation of the hull and it will right itself (usually). Or a sailboat can be knocked down (laying on its side), ease the mainsheet and she'll stand back up. But none of this has anything to do with the keel. It has to do with the ballasting.

Now, this Hunter is a FUN boat to sail. It does not have a more flat bottom like the Catalina's do. So it heels easily (more tender) at first, despite the heavy ballasting and long fin keel. You can run this boat with the rail under the water in 12-15 kt wind carrying full sail, but she won't go any further because the hull design causes it to "stiffen up" as the heel angle increases. It takes a big rogue wave to make her roll and pitch to knock her down. BUT - you're not using your keel effectively at that heel angle. The keel has to be more perpendicular under the boat to be most effective. So the boat is slow at excessive heel angle. Reef the main down and hoist a smaller jib (or furl it), then the boat sails with less heel, the keel is more effective, and she goes faster that she does carrying too much sail.

Other sailors will know what I'm talking about - bigger sailboats are nice for cruising with 4-6 people onboard because they have a lot of room. You can sail a bigger boat all day and get bored because it doesn't really do anything exciting. Smaller sailboats 18-26 feet are pure fun because they're so responsive to helm input and sail trim. And the type of keel she has under her will determine just about everything about her handling characteristics on all points of sail except a run.

Hope this helps folks understand better what the keel is all about on a keelboat. Powerboats have a keel too, but for the most part the bottom of a powerboat is pretty flat. This is kind of a humorous rundown of why we see some powerboaters have so much trouble with docking their boats :)
It's Not Your Fault!...Docking a Power Boat is Difficult | Docking
 

White90GT

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Jul 5, 2011
Messages
161
Re: keel weight?

This was a nice read, thanks for all of your input guys. My 14 y/o daughter has just gotten into Sea Scouts of America and I have been sailing with their troop on weekends now for a few outings. The troop gets boats pretty much on a donation basis.
The current boats they have:
Adrianna is a 16 foot (don't get me to lieing on the model of the boat or sail size). She has a fold down keel that I believe is 2.5'-3' long below the bottom of the boat. She has a nice size main and jib sail and is a very fun little boat to sail. One of the skippers and myself were sailing it back in from the bay in the afternoon and the wind kicked up. We were tracking a lot to get back to the launch because the wind was blowing away from the launch. We went to track and I forgot to release the jib sail as skipper started the turn, that was fun LOL. The wind caught the jib sail and pushed is over with water coming up over the side rail into our seating area, luckily skipper had a hold of the main sail and didn't have it locked down and released it before the boat could lay over completely.

Gulf Coast is a small sunfish, but we're still working on the rigging for it.

George is a small 14-16' boston whaler center console that we use as a chase boat and to pull the small boats away from the launch and out into the bay.

Fay's Lift is a 26 foot Westerly is kept down at the Marina about 10 minutes from my house. The skipper and I are going down there this evening to work on her and see if we can get the engine going again. It has a small diesel engine in it and the last time we took it out on March 29th, the engine was getting hot and died on us right as we got back to the boat slip. Skipper started replacing the seawater impeller, but broke a bolt off. We're going to try and fix that and get it sea worth so we can take it out this weekend to a Sail Days event at Houston Yacht club.

We also just got a Makita (not sure on name) Catamaran that needs a little work to be sea ready.
 
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