Three sided taper?

[Laxet]

I read recently on a boat building forum (real boats) that only three sides of a mast should be tapered. The aft side is left straight. Does this rule apply to our world? Is there an advantage of one method over another (other than ease of construction)? I'm working on Model Shipways brig Niagara, & am trying to taper the masts now.

 

Dale G Elhardt

[jud]

I can see some advantages with having the rear side of a mast with the fiber intact and running full length, not shortened by tapering.

jud

[DBorgens]

I don't know what the practice was for older ships. However, the Bluenose (1921) plans show the mast tapers are offset. The forward edge of the main mast and the aft side of the top masts are straight.

 

Dave B

[Laxet]

Hmm. I wonder what the reason is for that.

[wefalck]

Actually, wooden masts on 'modern' (i.e. from the late 19th century on) yachts often were not round, but oval or drop-shaped. There are several reasons for this: a) it increases the strength in longitudinal direction; it improves the air-flow to the sail, reducing eddies behind the mast; c) when using hoops for attaching the sail, it keeps it closer to the mast in the upper part; d) in the late 19th/early 20th a sort of T-slot was cut into the back of the mast, allowing the sail to be attached by feeding-in the bolt-rope (the same way as on modern, extruded aluminium masts).