BCC Mast Engineering Drawings

Hello All - we inquired with Forespar about getting a quotation for a replacement mast for Calypso. Calypso has a wooden mast - and while it’s still serviceable today, the day will come when it will need to be replaced. Forespar are no longer making masts. But they were willing to share their engineering drawings, which I have attached here if anyone ever needs them.


BCC mast and boom drawings from forespar.pdf (688 KB)

1 Like

Most valuable! You’re fantastic, Jeremy.

Note that Forespare modified the mast and boom, responding for example to customer requests and more.

I’d earlier posted the Forespar engineering diagrams for a few SLM Co. boats around the build date of BCC116 Zygote. The dates of the two diagrams differ not very much.

See: Boom: Sam L Morse Co hulls 100 to 116 (and perhaps more): Documentation




Ahoy Guys , for what it’s worth , BCC Calliste had a new 6061T6 aluminum mast extruded in Singapore . We purchased the extrusion die at USD 5 K and they extruded 5 each 20’ sections, a minimum run . We paid a little over USD $ 1000.00 for the 5 extrusions back in 2006-7 . We used the same foot print and wall thickness that Forespar used. Calliste’s first mast was a 1985 vintage Forespar mast where at least one of their extruded sections was butt welded together.


Did you guys ever get a new mast and boom?

Just curious who you guys went with- replacing the mast and boom on Cymba are on the long term re-fit list before heading offshore.


BCC #77

I used forespar for my mast in 2009 and it appeared very well done. However shortly after the paint began to flake off. I was told to contact their agent in Florida Mack sails. They came out and looked at it and advised of failure of bond apparently forespar were trying to get away from highly toxic chromates. Forespar were most unhelpful accusing me electrolytic damage.

The new bonding material in my mast was a dismal failure. After much wrangling and support from Colin Mack the mast was stripped and repainted. It has been perfect ever since. I believe forespar May have got out of masts due to problems.