Sailboat Masts

Building A New Mast For My 28ft. Wooden Sloop.
Need To Know The Formula That Would Give The Foot And Head Dimensions As Well As The Tapers.
This Mast Is A Piece Of Douglas Fir, From A 400 Years Old Tree,
Which Is A Piece Off The Bluenose 2 Schooner.
Suggestioms Appreciated.
Killick

 

If you are building a "new" mast for your boat can I assume you have the old mast still. The new should be modeled closely to the prevoius if they are the same conctruction.

Did your old one need replaceing because of age/general wear or breakage?

 

Original mast was aluminum and it broke at the spreaders due to a shackle failure at a chain plate on the deck.
I have a douglas fir replacement but am trying to find how to calculate the base and head dimensions.
The aluminum was just a straight up piece of metal.

 

Starting from scratch is a bunch of formulas according to my boat restorer. He says it is easier to just to fit one to a known sail plan and boat. He also mentioned the use the boat will see needs to be known, also something about standing layouts and ballast to displacement ratios which I did not completely understand.

 

Anyone with 'Skeene's Elements of Yacht Design' could answer your question if you provide the length of the mast, whether it is stepped on deck or keel, whether it is gaff or bermudan rig. Or if you find the book you could look it up yourself.

 

Figuring out the size of a new mast is an engineering problem, more complex than what can be obtained from a simple formula. Skene's does indeed show the procedure to follow, as does Principles of Yacht Design by Larsson and Eliasson. These procedures will show you how to calculate the size of the mast section in wood, its wall thickness, and the taper that can be used, all depending on the size, weight and stability of the boat.

Eric

 

Many thanks.
Killick

 

Good advice. thanks.
Killick

 

Is this mast going to be hollow or solid? My concern is weight. If you are putting a much heavier mast in the boat then you are going to see a noticeable change in roll and stability.

Just something to think about.