Thread: Solid wing mizzen on Beth, RAID41?

Howdy Clarkey,

The biggest single problem of wingsails is you cannot get rid of them when you need to.

The Biting Midge has the story of sailing on a large cat designed and owned by the great Lock Crowther - probably the greatest multihull designer in technical terms prior to his death in the '80s.

I will try to to justice to it.

Boat was 40ft plus with a narrowish but true wingmast. Rising wind and nightfall. Boat going faster and faster. Mainsail was dropped and Lock went below for a sleep, leaving the boat in the hands of the very capable crew.

Wind comes up more

Screeching gust and boat gets up to well in excess of 25 knots.

Lock rushed up from below and tells the Crew ... "Guys ... it is only a delivery trip and I don't like doing more than 20 knots at night ... we are not racing ... can you drop the jib?"

Biting Midge tells Lock ... "we dropped it half an hour ago".

Lock goes back down below carefully sliding the hatch shut behind him.
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However Clarkey ... even though the mizzen on Beth is very small it is a very active sail. It gets trimmed to each major point of sail to keep the help balanced and powered up. The mizzen sheet is quite active - not a feathered sail at all.

It makes a really significant contribution to the performance ... primarily because of balance upwind and a good deal of power downwind particularly broad reaching and running.

These are conditions where wingsails just don't work ... they rely on apparent wind to keep flow attached (ie the sail unstalled) so really are only suitable for quite fast boats.

By the way ... almost everyone has a misconception about goosewinging jibless yawls when broad reaching or running. The fast way to do it is to let the mizzen flop over naturally then gybe the main to be by the lee.. even if it has to go out slightly beyond square to stay out there.

This means that 100% of your sail area is working downwind unlike a sloop rig where the jib collapses unless you use a pole to hold it out. It can even mean the accelerated flow as the air tries to avoid the mizzen ends up in your mainsail. Like the trick of sailing between the left and right part of the fleet when you are ahead in a big race - the air comes through the gap a little faster.

Lugs and sprit ketches can be quite devestating in spinnakerless racing!

Best wishes
Michael

Thanks MIK. I told you that the question would show up my lack of knowledge!

How do you handle both sheets? I always presumed that the mizzen would be cleated off (but easily within reach!) and the main was played to keep the boat on its feet? Will I be in danger of running out of hands on RAID41?!

I think I will now nip down to the pub to think about something sensible instead!

Chris