If you have a lead keal the lead is heavier than water. With the water ballast boats you have water in water and both have the same density. then where is the ballast in the 240/260? I have a 240.
water ballast
- Thread starter Doug12976
- Start date
- Status
240 ballast
you have 1300 lbs of water in the ballast tank on a 240. It's not the difference in densities it's having the weight at the appropriate point. 1300 lbs of lead=1300 lbs of water = 1300 lbs of feathers any combination would result in the same ballast. Water ballast makes the boats easier to tow because you can leave your ballast behind. I also have a 240.
you have 1300 lbs of water in the ballast tank on a 240. It's not the difference in densities it's having the weight at the appropriate point. 1300 lbs of lead=1300 lbs of water = 1300 lbs of feathers any combination would result in the same ballast. Water ballast makes the boats easier to tow because you can leave your ballast behind. I also have a 240.
Another way to think about it is...
...that the water acts as a solid in a FULL ballast tank. It lays flat in the lower parts of the hull. Tip the boat on its side and the downward portion of the boat (air) is more boyant than the water it's in (the sea, lake or whatever) and the water in the ballast tank on the other side now above the water line in the upward part is more dense than the air and wants to go back down. If that confused you then do this at home experiment; fill a paper cup 1/3 full of water and freeze it. Then, float that cup of water in a full sink and try to tip it. Ice is actually less dense than water. These boats are more tender than a deeper metal keel as the mass is higher. Indeed a shallow keel vs. a deep keel of the same mass is more tender. Think of a see-saw in a park. I've been on a 260 keel and water ballast so had the opportunity to compare the same hull with the different ballast. alan
...that the water acts as a solid in a FULL ballast tank. It lays flat in the lower parts of the hull. Tip the boat on its side and the downward portion of the boat (air) is more boyant than the water it's in (the sea, lake or whatever) and the water in the ballast tank on the other side now above the water line in the upward part is more dense than the air and wants to go back down. If that confused you then do this at home experiment; fill a paper cup 1/3 full of water and freeze it. Then, float that cup of water in a full sink and try to tip it. Ice is actually less dense than water. These boats are more tender than a deeper metal keel as the mass is higher. Indeed a shallow keel vs. a deep keel of the same mass is more tender. Think of a see-saw in a park. I've been on a 260 keel and water ballast so had the opportunity to compare the same hull with the different ballast. alan
an article on water ballast
http://mywebpage.netscape.com/TedsSailingPage/waterbal.html If you can copy that address to your computer you will find an interesting article. I am not an engineer and I believe the article may not be absolutely correct. In any case take a look. I previously owned a water ballasted boat that had 1/3 of the water above the waterline in the permanent tanks. I had to pump that in. I just bought a used H-240.
http://mywebpage.netscape.com/TedsSailingPage/waterbal.html If you can copy that address to your computer you will find an interesting article. I am not an engineer and I believe the article may not be absolutely correct. In any case take a look. I previously owned a water ballasted boat that had 1/3 of the water above the waterline in the permanent tanks. I had to pump that in. I just bought a used H-240.
The ballast is in the tank, under the floor 
As Ken pointed out, water has a weight and that weight and its position in the boat are what provide the righting moment that we need to keep sailing boats upright. The water ballast article tried to point out that besides the weight, the location of the ballast matters, too. A deep lead keel has the weight some distance below the hull, which provides a longer moment arm to make the ballast more effective. 100 lbs of lead located 4 feet below the hull will be more effective at righting a boat than the same 100 lbs located only 2 feet below the hull, and both would be more effective than 100 lbs of lead in the hull. 100 lbs of water (about 12 gallons) will be just as effective as 100lbs of lead (which probably takes about the space of 2 gallon milk jugs) given the same distance below or in the hull. 100lbs of water takes up more room, so if you put 100 lbs of lead in the hull, it would take up less room. Other differences are that: + because the ballast tank is in the hull, it takes up space that could otherwise be used for a lower floor and better head room (compared to a lead keel attached to the bottom of the boat). + A fin keel has its mass more centered (fore and aft) than a water ballast boat which usually has the ballast distributed substancially front to back. This makes the turning moment longer (turns/tacks more slowly) for a water ballast, or even a full keeled boat, compared to a fin keeled boat. You get the same effect if you spin yourself in a chair. Hold your arms out, you spin slower than if you pull your arms in. Same effect for an ice skater that spins faster as they pull their arms in. A 24 to 26 foot WB sailboat is much easier and economical to trailer around compared to a fixed ballast boat of the same size. The ballast is borrowed for free and gets left behind. Lead/Steel/concreet ballast cost money and must be hauled around with the boat. Fair winds, Tom
As Ken pointed out, water has a weight and that weight and its position in the boat are what provide the righting moment that we need to keep sailing boats upright. The water ballast article tried to point out that besides the weight, the location of the ballast matters, too. A deep lead keel has the weight some distance below the hull, which provides a longer moment arm to make the ballast more effective. 100 lbs of lead located 4 feet below the hull will be more effective at righting a boat than the same 100 lbs located only 2 feet below the hull, and both would be more effective than 100 lbs of lead in the hull. 100 lbs of water (about 12 gallons) will be just as effective as 100lbs of lead (which probably takes about the space of 2 gallon milk jugs) given the same distance below or in the hull. 100lbs of water takes up more room, so if you put 100 lbs of lead in the hull, it would take up less room. Other differences are that: + because the ballast tank is in the hull, it takes up space that could otherwise be used for a lower floor and better head room (compared to a lead keel attached to the bottom of the boat). + A fin keel has its mass more centered (fore and aft) than a water ballast boat which usually has the ballast distributed substancially front to back. This makes the turning moment longer (turns/tacks more slowly) for a water ballast, or even a full keeled boat, compared to a fin keeled boat. You get the same effect if you spin yourself in a chair. Hold your arms out, you spin slower than if you pull your arms in. Same effect for an ice skater that spins faster as they pull their arms in. A 24 to 26 foot WB sailboat is much easier and economical to trailer around compared to a fixed ballast boat of the same size. The ballast is borrowed for free and gets left behind. Lead/Steel/concreet ballast cost money and must be hauled around with the boat. Fair winds, Tom
Alan - another way to think...
Alan, you said you had the opportunity to compare the 26 with a keel and water ballast. what were the differences you observed?
Alan, you said you had the opportunity to compare the 26 with a keel and water ballast. what were the differences you observed?
vikingvb, I've been in a...
...260 water ballast and a 260 keel (eventially renamed a 270) which has been discontinued. The 26 which is almost identical never had a keeled version. From what I could tell the hulls except for the keel itself were identical. To keep heel less than 15 degrees when beating to wind, the water ballasted version had to have canvas reduced at around 12 knots of wind. The keel version around 16. Of course these were only two boats. alan
...260 water ballast and a 260 keel (eventially renamed a 270) which has been discontinued. The 26 which is almost identical never had a keeled version. From what I could tell the hulls except for the keel itself were identical. To keep heel less than 15 degrees when beating to wind, the water ballasted version had to have canvas reduced at around 12 knots of wind. The keel version around 16. Of course these were only two boats. alan
- Status