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inamk · 20-10-2011, 23:10

Has any one experience of using chinese junk sail on a 30 foot and larger catamaran?

**James S** · 20-10-2011, 23:11

Have a look here.
junk rig - Google Search

This is all cruisers forum links.

barnakiel · 21-10-2011, 07:30

I would think at least two things may count:

- the junk rig does not point, many catamarans do not point, there seems to be some synergy here,

- the junk rig is often unstayed, it may be a bit difficult to put unstayed rig on a cat, so you will need one mast in each hull or a stayed rig, with a stayed rig you lose some of the benefits of the junk rig, with two masts you have two masts, two sails, etc.. so you will bear the extra cost,

b.

ocean_groover · 21-10-2011, 09:18

Somewhere out there in webland I came across a blog of a french couple who built a larger (50+ feet) Wharram and had a pair of unstayed junk rigged masts on it - one in each hull. They were happy with it. I've lost the link sorry. They also had hybrid electric drives, which is how I came across them.

I think the problem with putting one unstayed mast in the middle of a cat is there's not enough structure there for a decent bury, unless you beef up the whole area to the point where the weight gains become unacceptable. Maybe look at how those aerorig cats do it; there are a couple around. Windward performance especially in lighter airs is also, as noted above, reportedly an issue with junk rigs.

I stand to be corrected on this; there is elegance in simplicity, not to mention cost savings. Love to hear from anyone who's made it work.

Sand crab · 21-10-2011, 09:37

The aerorigs were generally mounted on top of the salon and penetrated through down to the cabin sole which gave it enough "bury" to support the unstayed mast. There is at least one cat with twin aerorigs with one in each hull. A junk rig could be done the same way but why would you want too. The great thing about cats is they are generally faster than their mono cousins. You wouldn't want to build the slowest multi ever. Cat2Fold and others have done unstayed winsurfer type rigs in each hull. There are 2 multis for sale built out of steel (a cat and a tri) so a junk rig would probably be third slowest. BOB
PS It is good to ask the question.

S/V Alchemy · 21-10-2011, 17:51

All you might want to know:

All in the Same Boat: Amazon.ca: Fiona McCall, Paul Howard: Books

tenchiki · 21-10-2011, 22:02

I owned a cat with unstayed junk rig in each hull. Fat, shallow hulls with inside leeboards. The masts were too far forward, requiring the hulls to be fat forward to support the weight of the solid, unstayed masts, and the leeboards didn't line up straight. It was a bear to tack, and forget it in light winds. in strong winds she did very well on a close reach, broad reach, or dead down-wind. SF-Bay conditions were good to sail in, It wouldn't have done any where near as well in a lighter wind area. It looked like it was "inspired" by (older) Wharrams, with soft beam mounts and an open cocpit & deck between the hulls. It was built much heavier than it looked -- you hit the dock, the dock yields... And that was probably another reason that it didn't sail very well. But, boy, was the junk rig easy to manage!

inamk · 21-10-2011, 22:36

My idea is to use the Junk Rig only in good winds on my 36ft displacement hull profile power cat which is designed to have a 120 hp diesel. max speed 14 knots, economic cruising at 10 knots.

The unstayed mast would be suitably supported and anchored in the bottom of the saloon. I expect to have the building started next month in a local boat yard which have been building wooden boats of up to 100 ft for the past 100 years.