Ballast Physics

[Tom Atkins]

Man I hesitate to ask this question but I'm ready to get my head chopped so - My cheap 22' boat with swing keel weights about 2,000 lbs and sails great. On rough days I of course bounce around like a pingpong ball. I see other high-end boats near my size that do great on rough seas (Pacific Seacraft/Seawards). They weight up to 4 times as much as my boat! What would happen if I added a ton (or two) to the inside of my boat? If the ballast was well placed and secured - would I be more stable in rough seas and live to brag about it?

 

[Clay]

Careful, it become displacement and not ballast

would be like adding salt bags in the trunck of you car during the winter for better traction, but isn't going to keep you on the road.

 

[Chris Burti]

Careful is right!

Several thing come quickly to mind.If your boat is lightly constructed, it may not have the structural integrity needed to carry your contemplated ton or two load. I suspect that having your boat come apart on a rough day might prove a bit distressing to you and your guests.Another likely result is that your freeboard will be substantially lowered by the weight of your cargo (I hesitate to call it ballast in this instance). It could be embarassing to be swamped and sunk by the wake of a passing jet ski.On light air days you will literally sail circles around those pricey, heavy displcement boats. You need to decide whether you are sailing predominantly in heavy weather or light air. Then, make it your goal to own a boat most suitible to your typical sailing conditions if your current lady isn't the right one. All boats are a compromise, your challenge is to find the one that makes you more happy than dissatisfied.Have fun finding out.

 

[CharlieCobra]

Ballast

My V-21 has a 400# swing keel. I thought of putting a 600# keel from a 24 on it so I could increase the sail area. I don't think the extra 200#'s would make much difference in freeboard but two tons??? That's a lot of weight.

 

[Drew]

Another thought...

Your boat's ballast does not exist in a vaccum, any more so than does the Pacific Seacraft's ballast. It is an intrinsic part of your boat's overall design - all the parts fit together. You can nail your "cheap 22' boat" to the dock in a gale if you want too, but if you raise sail the wind will rip the spars off. Not necessarily so with the PS, because each part/system is appropriate to the total design.Chris has the right idea below. Figure your needs and find the right boat for those needs.

 

[Clay]

I think

Now we chop off your head now Atkins, so you want to "live to brag about it", not happening.

 

[Roger5024]

Try Live Ballast

I have a Com-Pac Picnic Cat, 14 foot, centerboard, gaff-rigged catboat. It is remarkable how much better she sails with five people on board than with two in any strong breeze. But she only displaces 500 lbs. While she handles the breeze and the seas better loaded down, I would not take her into anything more than two feet of chop.My only other experience was in my former keel boat, a Catalina 27, displacing close to 7,000 lbs. The number of people on board made hardly any difference to her sailing or seahandling ability. So in good air but calm seas (if you can get'em) ask four friends out in your 22 and find out! The big advantage to 1000 lbs of people over 1000 lbs of sandbags is that you can movepeopke around the boat by asking politely.RogerKatty BayPC 123Cape Cod

 

[tom]

Everything is Related

Extra ballast means extra strain on rigging. Try reefing or using a smaller headsail when it's windy. My old Macgregor 26D would be a handfull when th ewind got over about 15 knots first I'd change the 150 to a working jib. Then put in a reef. Then a smaller headsail... then a second reef. If you haven't tried reefing you will be amazed at the large effect of reduction in sail area. In light wind the Mac was moving well when heavier boats were sitting still or motoring. But when the wind was up some of the heavier boats were faster.

 

[RichH]

Load capacity

A 22 ft. swing keel boat (Cataline 22) has an approximate 'pounds per inch' rating - how much more deeply the boat will be into the water for weight added - at about 530 pounds per inch of waterline immersion.At one additional ton of weight (2000#) that 22 ft. boat will be 3.8" deeper in the water than normal; at 2 ton (4000#) the boat will be 7.5" deeper than the normal waterline. How much freeboard do you have? A boat that is that deep into the water beyond its normal waterline is going to be as hydrodynamically efficient ...... as a 'brick'. ;-)

 

[Tom Spohn]

A relationship

exists between sail area and displacement. You can make the boat more comfortable in a blow by adding displacement (up to a point!); but then you will have a dog in light winds. It would be much easier to adjust sail area when it blows then you will still have a fast boat in the light stuff. Check this out for some ratios:http://www.image-ination.com/sailcalc.html

 

[OldCat]

Putting it Together . . .

Putting together the posts - your boat, or any decent boat - is a balance of hull design, ballast, displacement and strength. Change one factor, and you mess up the equation.Heavy, your boat will not perform, because it has a hull shaped for being light.More ballast will increase the loads on the mast and rig - because you don't heel over as far the sail will either be more upright to the wind, or you won't sheet out as soon. Either way, stress goes up and pop goes mast or shrouds.The thread is right - get a boat designed for how you use it, if you want heavy, get one that is designed that way from the start.A J22 or Catalina 22 is a good boat, so is a Pacific Seacraft - but they are designed for a different kind of sailing or budget. I like the former two for our local lakes, if I could sail off to Hawaii the choice would be different.