Deep draft or shoal draft
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Deep water or shallow???
The only advantage to shoal draft is tht you can sail in thinner water. Her along the gulf coast there is a lot of water that is only 10-12' deep. It is even thinner as you get close to shore. My boat draws 4.5' and there are times when it was less. the good news is that the botom is usually mud or sand and hitting it usually doesn't do any damage. For sailing for a given surface area a long deep fin is more effective going to weather. Also for a given amount of ballast the lower it is the more effective it is in keeping you upright. A full keel will hold course better but is usually slower and won't point as well. So unless you sail in thin water go with the deep fin keel for performance.
The only advantage to shoal draft is tht you can sail in thinner water. Her along the gulf coast there is a lot of water that is only 10-12' deep. It is even thinner as you get close to shore. My boat draws 4.5' and there are times when it was less. the good news is that the botom is usually mud or sand and hitting it usually doesn't do any damage. For sailing for a given surface area a long deep fin is more effective going to weather. Also for a given amount of ballast the lower it is the more effective it is in keeping you upright. A full keel will hold course better but is usually slower and won't point as well. So unless you sail in thin water go with the deep fin keel for performance.
No decision unless you are in very shallow waters
Christian: There is no decision to make here unless you are sailing in very shallow waters most of the time. Some of the folks in the NJ and Chesapeak Bay area have these concerns as well as Fl. Most of the rest of us can do fine with a 5' plus keel. It may be a little different if you are looking at a boat with 7 feet or more of keel, but that is really not that common. The biggest difference is in your ability to point higher.
Christian: There is no decision to make here unless you are sailing in very shallow waters most of the time. Some of the folks in the NJ and Chesapeak Bay area have these concerns as well as Fl. Most of the rest of us can do fine with a 5' plus keel. It may be a little different if you are looking at a boat with 7 feet or more of keel, but that is really not that common. The biggest difference is in your ability to point higher.
slower?
In a sailboat? there has to be 1000 other things on a sailboat that really matter when it comes to speed. If you want fast get a power boat, if you want fast sailing get a hobie cat. Now you want fast sailing and a cabin ? get a sailboat with all the sail you can find. There are so many variables that the lenght of ones keel is way down on the listwhen it comes to speed. If you are after speed throw everything overboard. You'll go faster then. Hull depth I guess really does matter in certain circumstances but I imagine the differance to the average sailor would be minisciule(sic).Going downwind, the one with the largest sail and lighter boat would win I know I'll get lots of responces to my post here but the lenght of ones keel has more to do with WHERE you sail.Deep keel = deep water. shoal keel means shallow water. See where I'm going with this? Keep it up, Ctskip
In a sailboat? there has to be 1000 other things on a sailboat that really matter when it comes to speed. If you want fast get a power boat, if you want fast sailing get a hobie cat. Now you want fast sailing and a cabin ? get a sailboat with all the sail you can find. There are so many variables that the lenght of ones keel is way down on the listwhen it comes to speed. If you are after speed throw everything overboard. You'll go faster then. Hull depth I guess really does matter in certain circumstances but I imagine the differance to the average sailor would be minisciule(sic).Going downwind, the one with the largest sail and lighter boat would win I know I'll get lots of responces to my post here but the lenght of ones keel has more to do with WHERE you sail.Deep keel = deep water. shoal keel means shallow water. See where I'm going with this? Keep it up, Ctskip
Keel length probaly more important
Keel length is probably more important when it comes to where you anchor than where you sail. Drawing 4 feet or 6 feet doesn't matter that much most places. But when the sun starts down and you want a place to spend the night a couple of feet can make a lot of difference. Even in Mobile bay with it's average 12' depth almost any sailboat can sail almost anywhere. But when you try to get into a cove to anchor even my 4.5' can be too much. Usually there is some sort of bar that you need to cross to get into deeper water. I guess if you are patient you can plan to enter and leave at high tide. But if high tide is at noon and you are having a great time sailing calling it quits mid day would suck. tom
Keel length is probably more important when it comes to where you anchor than where you sail. Drawing 4 feet or 6 feet doesn't matter that much most places. But when the sun starts down and you want a place to spend the night a couple of feet can make a lot of difference. Even in Mobile bay with it's average 12' depth almost any sailboat can sail almost anywhere. But when you try to get into a cove to anchor even my 4.5' can be too much. Usually there is some sort of bar that you need to cross to get into deeper water. I guess if you are patient you can plan to enter and leave at high tide. But if high tide is at noon and you are having a great time sailing calling it quits mid day would suck. tom
my last thought
Buy a chart(s) of the places that you intend to sail and anchor. If you mostly see water over 7' then a deeper keel will be fine. If you see a lot of water less than 5' you may want a shallower keel. I have a friend on Mobile bay that has a sailboat with 6.5' draft. He is happy with the boat even though there are places he can't go. tom
Buy a chart(s) of the places that you intend to sail and anchor. If you mostly see water over 7' then a deeper keel will be fine. If you see a lot of water less than 5' you may want a shallower keel. I have a friend on Mobile bay that has a sailboat with 6.5' draft. He is happy with the boat even though there are places he can't go. tom
How I decided
When I was making that same decision, what helped me decide was determining how tiny the benefit was to the deep draft. Knowing the benefit was pointing higher, which can equate to faster, I thought to look at the PHRF racing system to get a measure of "how much" faster. When I took a look at the PHRF ratings for the model sailboat I am buying (Beneteau 393) with each type of keel, and saw that that the shoal draft keel only added 3 to the rating (on a base of 129) ... I decided that was far too tiny to call it a benefit! I am not entirely sure exactly what 3 equates to, but I think it is 3 seconds per nautical mile. So if I sail 100nm tommorow, it will take me an extra 5 minutes (on average) with a shoal keel. However, I will have greater peace in shallow water and more choices of anchorages when I get where I am going. I have more than made up for the 5 minutes, by getting a classic mainsail (with low friction slides) instead of furling, and a feathering propeller.
When I was making that same decision, what helped me decide was determining how tiny the benefit was to the deep draft. Knowing the benefit was pointing higher, which can equate to faster, I thought to look at the PHRF racing system to get a measure of "how much" faster. When I took a look at the PHRF ratings for the model sailboat I am buying (Beneteau 393) with each type of keel, and saw that that the shoal draft keel only added 3 to the rating (on a base of 129) ... I decided that was far too tiny to call it a benefit! I am not entirely sure exactly what 3 equates to, but I think it is 3 seconds per nautical mile. So if I sail 100nm tommorow, it will take me an extra 5 minutes (on average) with a shoal keel. However, I will have greater peace in shallow water and more choices of anchorages when I get where I am going. I have more than made up for the 5 minutes, by getting a classic mainsail (with low friction slides) instead of furling, and a feathering propeller.
Centerboard is an option
The ocean near me is deep but the rivers and bays I visit are not, so shoal draft with a centerboard was my choice - 4'2" board up, 8' 3" board down. When the board is down it helps me point higher which means a faster trip if I'm going to windward. If I was racing a lot or not venturing to shallower waters, I would go with a deep fin keel. If I was sailing offshore (passage making)a lot, I would go with a deep full keel.
The ocean near me is deep but the rivers and bays I visit are not, so shoal draft with a centerboard was my choice - 4'2" board up, 8' 3" board down. When the board is down it helps me point higher which means a faster trip if I'm going to windward. If I was racing a lot or not venturing to shallower waters, I would go with a deep fin keel. If I was sailing offshore (passage making)a lot, I would go with a deep full keel.
New or used boat? Old or new boat?
If you're in the used boat market, I wouldn't let the type of keel be too much of a factor in your choice of a boat. There's lots things to consider when buying a used boat. The keel's just one of them. On the other hand, by what I've read, wing/shoal keel performance has gotten closer and closer to fins over the past 20 years. The older the boat design, the more the difference between the two.
If you're in the used boat market, I wouldn't let the type of keel be too much of a factor in your choice of a boat. There's lots things to consider when buying a used boat. The keel's just one of them. On the other hand, by what I've read, wing/shoal keel performance has gotten closer and closer to fins over the past 20 years. The older the boat design, the more the difference between the two.
The purpose
of a weighted keel is to provide a righting moment to keep you sort of upright. A 2000 lb. keel with center of gravity (of the keel) 3 feet below the boats center of boyancy gives the same righting moment as a 4000 lb. keel 1.5 feet below the center of boyancy. So the deep keel boat can be lighter, push less water, and therefore faster, more nimble, and more fun to sail. Shoal draft keels, on the other hand, are better for shoals.
of a weighted keel is to provide a righting moment to keep you sort of upright. A 2000 lb. keel with center of gravity (of the keel) 3 feet below the boats center of boyancy gives the same righting moment as a 4000 lb. keel 1.5 feet below the center of boyancy. So the deep keel boat can be lighter, push less water, and therefore faster, more nimble, and more fun to sail. Shoal draft keels, on the other hand, are better for shoals.
Righting moment
To add a little to what Andy says, my understanding is that wing keels can make up for a portion of the loss of depth by providing hydrodynamic resistance to heeling due to their shape, and also can put more of their weight at the very lowest point of the keel. Deep keels still have the most righting moment. The other purpose of keels is to provide lateral resistance, and there are tons of materials available on the merits of fin vs. full keels, etc. Because I absolutely need to clear a particular sand bar, I opted for a lifting keel, yet another solution, and like all of them a compromise and tradeoff.
To add a little to what Andy says, my understanding is that wing keels can make up for a portion of the loss of depth by providing hydrodynamic resistance to heeling due to their shape, and also can put more of their weight at the very lowest point of the keel. Deep keels still have the most righting moment. The other purpose of keels is to provide lateral resistance, and there are tons of materials available on the merits of fin vs. full keels, etc. Because I absolutely need to clear a particular sand bar, I opted for a lifting keel, yet another solution, and like all of them a compromise and tradeoff.
A wing keel
looks and acts a lot like a bruce anchor. A friend has one on his catalina 34. He said that he can get into shallow water but once the keel hits it is extremely difficult to get off. If possible he waits for the tide to lift him off the bottom.
looks and acts a lot like a bruce anchor. A friend has one on his catalina 34. He said that he can get into shallow water but once the keel hits it is extremely difficult to get off. If possible he waits for the tide to lift him off the bottom.
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