This was valuable information. The boat is a 1984 and in exellent condition. The spreaders are swept back, but I did not know it was caused by the spreaders. What would be the advantage of the mast leaning aft ? or is it a disadvantage ? What suggestions do you have. Sorry to ask so many questions we are pretty new at this if you can't already tell. Thank you, Karen
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Mast Rake
The leaning of the mast aft is generally termed as "rake", as in mast rake (I guess this is the spelling). On a 50ft mast the rake might run 6 to 8 inches, order of magnitude. When a sailmaker measures up the mainsail they will hoist a plumb line up the main halyard and measure the rake. Some rake helps with the aerodynamics so the boat will sail faster. Next time you're near the marina on a Saturday morning, look around at the hotshot boats, the Meldges 24, catamarans, etc., and they all have their masts pretty severly raked back. I used to race a Falcon daysailer, 16ft, and in the first race of the nationals I placed something like 7th, then I raked the mast aft a few inches (short mast) and placed 3rd then 2nd. It was my feeling that I could actually feel the boat going faster and perform better. To give you a really scientific reason for the rake and the amount, I can't, but I know there are various forces at work. For example, the tell tails fly horizontal on both sides of the jib luff when the air is laminar and ditto on the main (but there are not tell tails on the main luff). There can also be a vertical component to the air over the sail - this is why Alaska bush pilots have vertical metal strips on the top of their main wings and droupy (sp?) wing tips - in order to prevent the air from going sideways down the wing. This helps them to land and take off at slower speeds and prevent the wing from stalling. I'm not saying this has anything to do with mast rake but only providing an example of things that can be going on that I can't explain. A mechanical or aeronautical engineer could probably give more insight into what's hapening. Advantage? Probably makes the boat go faster. Secondly, minor, if the forstay is not too tight one can loosen and remove the backstay and not have the rig fall down. Loosening the stays at the same time is advisable - put masking tape on the threads as a reminder where they were. May be useful at haulout time if a travel lift is used although most travel lifts should be able to handle a boat this size without removing the backstay. Suggestions? From what I've read, seems good as is. The backstay, in the loosest position, should feel a little loose but not sloppy-loose. The goal is to provide for some headstay sag when going downwind, and when tightened, to remove some of the sag. The jib is designed with a certain amount of sag which a sailmaker could provide. Order of magnitude, guessing, around 7 or 8 inches??? in your case. Another suggestion might be to check out a library book on triming sails and read all the magazine articles on the subject. The new Sail magazine that I just received has an article on triming your main; think the cover has a catamaran with green water. Follow the mechanics of what they talk about and keep your ears open for, say, an engineer (mechanical or aeronautical), or someone whith that kind of background, to help with the hows and whys. When the boat is sailing to weather under a fair load, check the tension on the lee stays - they should not be really loose. If they are, recommend talking to a rigger. Brian Toss of Port Townsend, WA, wrote a book recently on tuning the rig and he's very familiar with the B&R rig. I like your questions, they're a bit of a challenge to answer but good for the forum. Hope my answer isn't too long winded!
The leaning of the mast aft is generally termed as "rake", as in mast rake (I guess this is the spelling). On a 50ft mast the rake might run 6 to 8 inches, order of magnitude. When a sailmaker measures up the mainsail they will hoist a plumb line up the main halyard and measure the rake. Some rake helps with the aerodynamics so the boat will sail faster. Next time you're near the marina on a Saturday morning, look around at the hotshot boats, the Meldges 24, catamarans, etc., and they all have their masts pretty severly raked back. I used to race a Falcon daysailer, 16ft, and in the first race of the nationals I placed something like 7th, then I raked the mast aft a few inches (short mast) and placed 3rd then 2nd. It was my feeling that I could actually feel the boat going faster and perform better. To give you a really scientific reason for the rake and the amount, I can't, but I know there are various forces at work. For example, the tell tails fly horizontal on both sides of the jib luff when the air is laminar and ditto on the main (but there are not tell tails on the main luff). There can also be a vertical component to the air over the sail - this is why Alaska bush pilots have vertical metal strips on the top of their main wings and droupy (sp?) wing tips - in order to prevent the air from going sideways down the wing. This helps them to land and take off at slower speeds and prevent the wing from stalling. I'm not saying this has anything to do with mast rake but only providing an example of things that can be going on that I can't explain. A mechanical or aeronautical engineer could probably give more insight into what's hapening. Advantage? Probably makes the boat go faster. Secondly, minor, if the forstay is not too tight one can loosen and remove the backstay and not have the rig fall down. Loosening the stays at the same time is advisable - put masking tape on the threads as a reminder where they were. May be useful at haulout time if a travel lift is used although most travel lifts should be able to handle a boat this size without removing the backstay. Suggestions? From what I've read, seems good as is. The backstay, in the loosest position, should feel a little loose but not sloppy-loose. The goal is to provide for some headstay sag when going downwind, and when tightened, to remove some of the sag. The jib is designed with a certain amount of sag which a sailmaker could provide. Order of magnitude, guessing, around 7 or 8 inches??? in your case. Another suggestion might be to check out a library book on triming sails and read all the magazine articles on the subject. The new Sail magazine that I just received has an article on triming your main; think the cover has a catamaran with green water. Follow the mechanics of what they talk about and keep your ears open for, say, an engineer (mechanical or aeronautical), or someone whith that kind of background, to help with the hows and whys. When the boat is sailing to weather under a fair load, check the tension on the lee stays - they should not be really loose. If they are, recommend talking to a rigger. Brian Toss of Port Townsend, WA, wrote a book recently on tuning the rig and he's very familiar with the B&R rig. I like your questions, they're a bit of a challenge to answer but good for the forum. Hope my answer isn't too long winded!
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