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Ballast Princess


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Guest Scott Dunsworth
Posted

How is the Ballast made on the Princess? Do I need to start studying up on casting lead? I am going to build the 26 someday here after I get my shop extended about eight feet. Allreadey got the wife informed and got her setteled down. Actually I think she just surrendered. So inbetween working, sailing and a big list of honey do's I gotta get the shop done.

Has anyone heard about casting a ballast out of epoxy, lead pieces and lead shot? Seems like they made a mold lined in plastic. Then they would pour a layer of epoxy and some lead shot in the mold untill the epoxy was full. Then add another layer of epoxy and more shot untill the mold was full. The bolts where drilled out after it cured. Looks like you could cast the bolts in from the start to me though.

The ballast is something I won't be looking forward to, perhaps because I have never made one.

I don't remember where I read about casting a lead ballast that way. It seems like it would work allthough it would not be as heavy as a sold lead cast per square inch. And allthough not cheap it would be a heap easyer.

Any thoughts would be appreciated.

Scott


Posted

I've heard of a similar concept, using "boiler punches" which were cast iron scraps embedded in concrete. It had to be sealed well against the water, as the cast iron would rust, causing the concrete to crumble as it corroded away. The epoxy idea sounds like it solves at least part of that problem, and lead the other part.

A lot of guys use old tire weights from the local tire shops as a source of lead when they pour castings. I wonder if they would work in epoxy as a substitute to buying lead shot?

Posted
Has anyone heard about casting a ballast out of epoxy, lead pieces and lead shot? Seems like they made a mold lined in plastic. Then they would pour a layer of epoxy and some lead shot in the mold untill the epoxy was full.

I talked to Graham at length on this subject. The ultimate answer?? NO. you can not achieve the same density to area with epoxy and shot (or anything else).

Graham has the ballast located and designed for a solid cast ballast. If you deviate from this (cast), you will be on your own to best locate it in the keel.

Casting lead is really no big deal. the big deal with #250-#300 is the volume you are dealing with. Thus, a very large crucible and rig to hold and despense it!! :) I started casting ingots out of wheel weights for the Princess a long time ago. I have well over #100 at a cost of about $25. I cast them into 10-15 pound bricks, in a bread pan.

Long story short, yes you will have to study up on casting. Build a mold and prepare!! Heck, I have a lot of really cool weaights to help hold things in place as glue sets up now! :) :) ;)

Guest Anonymous
Posted

Thanks for the thoughts and insights.

I realized that the density would not be the same considering there would have to be voids in-between the pieces of lead.

In my amateur way of thinking, extending the ballast length three or four inchs on both ends may be enough to make up for the lost density overall.

If extending the length of the ballast would not be acceptable or would noticeably affect the performance from a saftey standpoint, I will just forget the ideal and stick my head in the sand. Then start studing up on melting and casting the real thing. ( I am kind of scared of the fumes )

I thought sence,I, be, a hard head, that I would cast a cubic inch of lead epoxy and see what it actually weighs. If someone could tell me what a cubic inch of lead weighs? I will post the results in a few days.

Thanks for your comments. I started to post this question on the woodenboat forum also, but I don't fill comfortable even talking about plywood there anymore, let alone anything that is not nineteenth century traditional.

Scott

Posted

It is always a battle with a shoal draft boat to get the CG low enough to get an adequate range of stability to recover from a knock down. Lead is the obvious choice for ballast because it is the densest material that we can reasonably work with. Lead is not that hard to work with once you overcome the fear of the unknown. There was a good article on a backyard pouring of a keel in the previous issue of Boat Builder magizine (the amatuer version).

When I tested cement and steel punchings I ended up (because of the shape of the punchings) with about 50/50 steel and cement. I think that you could do a little better say 60/40 which would mean that to keep the vertical CG of the ballast in the same position it would cost you around 1 1/2" in draft.

Graham

  • 2 weeks later...
Guest Scott Dunsworth
Posted

The one cubic inch of my epoxy lead mixture came in at a shade over 5 oz. Which comes to 540 pounds per cubic foot. If my math is correct that is about 76 percent of the one cubic foot of lead. The way I see this is, the ballast size could be increased 25 percent and have the same affect. Anyway casting a ballast this way would be easy but costly.

So I am going to start digging up lead from salvage yards and try to cast one the real way.

  • 2 years later...
Posted

I need to find what sort of equipment and where to get it for casting with lead for this PS26 project. Years ago I used lead for plumbing cast iron joints, but the pots were not very big and the ladle only held a few pounds at a time.

Charlie, what sort of rig did you use for the PS22? I recall seeing pics of the mold and the pouring.....I will do a search....maybe you already related this. :)

Thanks,

Greg.

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