Technical Article # Original Issued Date Latest Update
_003_ March 2, 2006 March 2, 2006


Ballast Densities — Material Choices and Use

Many factors affect the stability of a sailboat, maximum deck beam, maximum waterline beam, sail area to displacement, sail area to ballast weight, height of center of effort, sail area vs. draft, condition of the sails, hull shape, the captains’ ability to handle the boat, etc., etc., etc.

But to address one of the major factors in general stability, ballast material used.

Precision Boat Works only uses cast lead, and here is why:

1. Cast Lead Weight—708 pounds per cubic foot.

2. Cast Iron Weight—450 pounds per cubic foot.

3. Concrete Weight--140 pounds per cubic foot. (Avg. of normal aggregate mix)

4. Sea Water Weight—64 pounds per cubic foot.

5. Fresh Water Weight—62 pounds per cubic foot.

Pretty easy to see what material you want on your boat to provide sailing stability?
Most of yacht design is just math……………………………..and this math is pretty telling.

And note that lead, by way of being heavier & denser (efficient), it also takes up less far less space in your cabin (many cast iron swing keels protrude into the cabin) Our lead is below in the keel, more room in the boat, and as deep as we can put it.

Which also means that being denser; our keel section can be smaller. Which translates to less wetted surface, more stability…….and better sailing traits. And lead does not rust like cast iron, far less maintenance & expense.

The downside? More expensive, but it is the right thing to do.

As you see on much larger boats and much more expensive boats, lead keels.

Not iron.
Not concrete
Not water.

Precision……..Lead. There is a very good reason lead is used by leading large yacht builders, and…………………………………….by Precision Boat Works!

Note the location of the Lead Ballast on the left in drawing below.

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