Curved mast

[Lykke]

To distract ppl from the “monos are faster than multis because they can be raced at 95% as opposed to 75%” thread, here’s a question about something I saw the other day:

It looks like a Farrier 41 cat to me, but I don’t know. So why would you want a curved mast? What does it achieve that more rake doesn’t? Would it make it hard to make a mainsail that fits? If it is in fact a Farrier, Ian must’ve written something about this?

 

[El Borracho]

Gets the mast butt out of the salon while keeping the center of effort aft. The curve gets more sail area up high and creates a more efficient elliptical shape. Looks cool, too.

 

[Jethrow]

It also flattens the sail as you reduce rotation, good for depowering.

 

[MRS OCTOPUS]

To distract ppl from the “monos are faster than multis because they can be raced at 95% as opposed to 75%” thread, here’s a question about something I saw the other day:
View attachment 557402

It looks like a Farrier 41 cat to me,

Nah
Crowther design #150.
Prebend can do a couple of of things.
1, minimise mast pumping.
2, make the sail camber increase as the mast is rotated.

woops jethro got the camber whilst I was posting.

 

[Zonker]

Farrier F44 not the 41 (I think) or a Lock Crowther 45

 

[El Borracho]

It also flattens the sail as you reduce rotation, good for depowering.

That is clever.

 

[plywoodboy]

Crowther Super Shockwave ex Free Spirit

 

[JIAFox]

Also easier to Hoist a fully batten sail aswell.

 

[Keith]

Crowther design number 150.

Stuart Bloomfeild and Brett Crowther were involved in the rotating carbon rig design.

 

[boardhead]

Nah
Crowther design #150.
Prebend can do a couple of of things.
1, minimise mast pumping.
2, make the sail camber increase as the mast is rotated.

woops jethro got the camber whilst I was posting.

Spot on!

 

[nota]

is this on bigger boats a carbon is so strong thing
that they do not need to be in column ?

guess the form drag is better with a bit of curve then strait

 

[Marty Gingras]

is this on bigger boats a carbon is so strong thing that they do not need to be in column ?

Thinking out loud.

All else being equal, getting out of column is largely a compression thing.

All else being equal, shroud base is so wide on multihulls that compression must be wildly less than on a monohull.

The masts in this thread have such a large cross section that --- w/o much compression --- being out of column isn't an issue.

Just looking at the masts and rigging in this thread, it seems likely the masts were constructed with bend.

 

[teamvmg]

PITA to hoist the sail though

 

[longy]

My take: this is a racing technique not really suited for even a racer/cruiser. Curved mast may let you flatten the sail out more than a straight mast, but you still have full sail up. Might be an advantage to eek out the weather mark without reefing, but requires advanced & continuous trimming to work & not capsize. Any boat not racing will just reef. Maybe a bit slower, but much less danger, & much less stress.

 

[he b gb]

PITA to hoist the sail though

When ordering my sails I carefully measured the mast curve and did an accurate drawing drawing for the sailmaker.(the sailmaker was in Sydney and boat was in Queensland).
He must have done a good job as the sails go up easily by hand only needing the winch to tension and also come down easily with basic 7/8” slides.
The curve in the masts gives extra sail area (like a roach on the front of the sail) without the extra sheeting power needed for a large roach on the rear of the sail.

 

[boardhead]

My take: this is a racing technique not really suited for even a racer/cruiser. Curved mast may let you flatten the sail out more than a straight mast, but you still have full sail up. Might be an advantage to eek out the weather mark without reefing, but requires advanced & continuous trimming to work & not capsize. Any boat not racing will just reef. Maybe a bit slower, but much less danger, & much less stress.

The boat in question is Kite, home to a couple and their one year old. Mostly sailed single or short handed, very swftly and safely, up and down the east coast, NE in summer, Bahamas and beyond in winter.
Not raced but that rig works like a charm.
Hopefully the owner will spot this discussion and chime in.

 

[PIL66 - XL2]

The boat is Kite, a Crowther 150 owned by a member here ....M Rybas
Awesome cruising boat

 

[boardhead]

Really doesn't get much better than that!

 

[mrybas]

Hi Guys,
Kite is my boat (ex What’s up Doc….owned by another SA member @Keith)

Lock Crowther 150 built in NZ in ‘91.

Mast was built by @Keith after dismasting the original stick from Fiji to HI. Mast was designed by Stuart Bloomfield and Brett Crowther. 64’ carbon. No prebend, the curve is built into the mast.

I can raise the mainsail solo by hand (no winch). The main was built by OneSails NY. The luff of the sail matches the mast bend.

 

[Keith]

She's a beauty, eh.