Floatation Question

[Carl Simmons]

I would like someone to verify my floatation requirements that I have calculated.

The Lightning will weight 700# with 130# being the centerboard. That means 570# will be the actual boat. Since this is a wood boat it will weight roughly 60% in the water or 342#. Add back in the weight of the centerboard and the total weight is 472#. To add enough bouyancy to keep the centerboard top the floatation should support 120% or 566#. Since the boat will be used in fresh water as well as salt water the weight of a cubic foot of fresh water is 62.5#. Thus I figure I will need about 9 cuft of floatation (566/62.5).
Does this seem about right?

Carl.

[Wayne Jeffers]

Carl,

I think your first priority should be to set up the flotation so that in the event of a knockdown the boat can be self-rescuing. I think that is a little different twist on your question.

To be self-rescuing, you first want the boat to float high on its side after a knockdown. Lighting class rules require flotation in the mast above the spreaders, IIRC, so that should help keep her from turning turtle.

Next, you want to ensure she floats high enough on her side so that you can put your weight on the centerboard and turn her upright again with a minimum of water in the cockpit. This suggests that you should have adequate flotation positioned along each side.

If the boat is set up this way, you can right it with little water inside. The remaining water can be handled by suction bailers once you get underway again.

How much flotation that requires for each side, I'm not sure. Have you checked the Lightning class site for guidance? Or perhaps the class specs stipulate a minimum amount of flotation?

The boat continues to look great, BTW!

Wayne