Greetings!
Just in case the Stevenson Co. is really gone for good and I'm unsuccessful at finding a set of Weekender plans to buy from one of you, I was wondering if it would be possible to convert a Bermuda/marconi rig on another design I like to a gaff rig (without having to earn a Ph.D. in Sailing Physics, that is). If anyone has done this, or if you can direct me to other people, books, websites, etc., which could be of help, it would be greatly appreciated!
Thank you in advance for your help!
I had a question, about 3 weeks ago, about using a different sail then the boat plan called for. Paul Riccelli responded with:
Quote:Make a scale drawing of your sail, say 3/4" to the foot, which is a handy size. Then measure away from the tack, exactly 1/2 way along the foot. Do this again along the luff, marking both spots. With a straight edge draw a line from the peak of the sail through the mark on the foot and another line from the clew to the mark on the luff.
This "X" is the CE of the sail.
Do the same with the prospective sail you may purchase. Using a side profile of the boat (again a scale drawing) place both sails over top of each other so that the X's align over each other. Does the mast seem to fall pretty much in the same place? If so you can use the sail. If not, it's not a waste of time, but you might have to move the mast to insure both sails share the same CE location. Fortunately the lateen rig is pretty forgiving if the mast is moved around a little, but the CE has to be the same as the original or the boat will balance incorrectly.
I made 4 little sails and checked them out in regards to the boat I am building. It was fun and left me with 4 small paper sails and a small paper boat. It also showed me that the shape and size of the sail makes a big difference. You could try that to see if a gaff rig would work or what shape/size of gaff rig you would need?
The typical problem with a Bermudian to gaff conversion is the CE moves aft a fair amount with the gaff mainsail. On most Bermudian masthead sloop rigs, the CE is just aft of the mast centerline, generally within a few inches. Of course this varies substantially with headsail/main proportions.
So, if you want to use the chain plate and mast step locations from the Bermudian rig, the gaff rig tends to be too far aft. Also on most gaff rigs the proportion of headsail to main is much different, usually the gaff headsail is considerably smaller.
It can be done, maybe with less then ideal headsail/mainsail proportions, but it's possible.
The trick is to determine the CE for the whole rig (main and jib), then place the new rig's CE over this vertical reference. In fact it works best if the gaff CE is slightly aft of the Bermudian, because the "lead" required for a lower aspect gaff rig is less then that needed for a Bermudian.
If you have the luxury of being able to move the mast and chain plates, then a lot of problems are eliminated.
What Bermudian rig are you looking to convert (make, model and year)?
Paul,
The boat I'm looking at is the "Petrel" from Svenson's site:
http://www.svensons.com/boat/?p=SailBoats/Petrel
According to the article, the open cockpit and cabin versions have different mast positions, so moving the mast further forward still might be practical.
Petrel is a pretty famous design and it does have two different Bermudian rigs. You'll note there is a bow sprit on the cabin boat and the jib is tacked inboard of the stem on the open version.
It certainly could be done, but again, you'll need help locating the centers, so the balance of the boat isn't affected.
Kurt,
look at "Blue Moon" at the same site... it already has a gaff rig. The cabin top isn't too pretty, but that is easy enough to change.
Larry C