Possible to convert from Bermudan to Gaff? Rigging question...

I have a typical Bermudan sloop, and was wondering if it is possible to convert it to a Gaff mainsail. I'd do the single-halyard gaff setup as seen here: http://www.jakatan.com/jakatan_011.htm

I was also considering converting to a double-headed sloop. A short sprit of just a couple feet for the roller-reefing genoa, with an inner stay for a self-tacking jib.

While I'm sure I could handle the headsail changes, I'm not sure what I'd have to do with regards to the rigging to convert it to a gaffer. The back-stay would certainly be in the way... The mast is deck-stepped so it doesn't contribute any stability.

 

A gaffer will be lower and more spread out fore and aft----- so the mast would, all things being equal, be further forward and the sail leech further aft as well.
The shrouds would now trail aft, and the chain plates would now be angled too.
Whether deck or keel stepped shouldn't matter.
You would likely want to set up running backstays and stick with smaller headsails.

 

Ah, I meant without relocating the mast. This is a boat already in existence, not on paper.

 

Not a very good idea..It could be done but an avarage bermuda as the boat in question needs major re-planning and building to get a reasonably good gaffer. Gaffers "like" longkeel and displacement with a big D

 

Thanks Teddy.

What if the hull already had a full keel with cut-a-way forefoot?

 

Hi,
if the boat in question is an old fashioned bermudan sloop with a low aspect ratio main and long mainboom, with a relatively small jib. Then a conversion to gaff rig may be reasonably easy. If she is a high aspect ratio main with short boom and large foretriangle then forget it, it will be more work and expense than it is worth.
The things to bear in mind are that the gaff sail center of effort will be further aft than the bermudan, and must be balanced by an outer jib on a bowsprit which may need to be five or six feet outboard of the bow. The shrouds will need to angle aft by about ten degrees to give adequate support to the mast and you will need running backstays for off the wind sailing.
It is not essential to have a long keel and lots of displacement, a gaffer can be designed with split keel and rudder and if her ballast is reasonably deep then it need not be that heavy. It is a matter of designing the rig to suit the hull. A gaff rig has a lower center of effort than a bermudan rig so can set more area for the same ballast righting moment.

Best of luck with the project

David

 

Draw up a sail plan for the boat you currently have, including it's underwater profile. This may be available in some literature about your yacht or you could contact the designer. A reasonably accurate one could be drawn up from photos and measurements you take from the actual sail plan.

Find you CE and CLP, then draw up a gaff rig so the CE lives in pretty much the same vertical dimension ( * ) as the Bermudian sail plans carries it. This will retain your helm balance.

* Depending on your underwater appendage configuration, you'll need to adjust the CE/CLP "lead" to suit the gaff rig you install, which typically needs less then most Bermudians.

On most of these types of conversions the mast usually has to move to account for the proportionally smaller fore triangle of gaffers and of course the much longer boom. Even if you can arrange a gaff rig with the CE in a reasonable location, it's very unlikely the chain plates and other deck hard points for the Bermudian rig can be reused on the gaffer. This would require extensive strengthening in the new areas where runners and shrouds will land, not to mention tracks, winches, pad eyes, etc.

The short answer is yes it can be done. The real world answer is you'll need some skillful design and engineering efforts to pull it off and have the yacht balance nicely.

This isn't a job for a novice (not that I'm suggesting your are), but should be carried out with design help and solid installation/fabrication skilled worker(s).