This is my first season with my 2001 H240. One of the things I have noticesd is that the mast bends aft once she is fully rigged. I have seen this before and know it has to do with sail shape, I was just wondering if this can/should be adjusted in any way and what is the optimal mast bend for optimal sail shape? Thanks in advance for any adivice/help. Gary Compass Rose
Main Sail Shape
- Thread starter Gary16360
- Start date
- Status
Tuning the rig
You need to adjust the mast rake for optimum sail shape. There should be a section in your owners manual on "Tuning the B&R rig".
You need to adjust the mast rake for optimum sail shape. There should be a section in your owners manual on "Tuning the B&R rig".
Sail Shape
Mast bend helps you control the amount of power you'll get out of the main. Since there is no running backstay (nor is there a Cunningham) on the 240, I don't think you have as much flexibility for depowering by flattening the main as you would on a boat that has those features. If the vang and outhaul on a 240 are already maxed (assuming the main was hauled all the way up - look for the black masking tape near the top of the mast) there is nothing else that I am aware of (short of easing out the main and/or reefing) that you can do with the rigging while underway to depower. In a boat with a running backstay, putting bend in the mast by tightening the back stay will flatten the sail and depower it. I guess the point of all this is that when you are tuning the rigging, you might want to think about the prevailing conditions you are sailing under and put in the amount of prebend for those conditions, i.e., if you constantly sail in heavy wind, then you might want to put more prebend in the mast. Although it will slow you down in lighter air, it will give you more control in heavier air and, in my view, allow you to hold off on reefing just a bit longer. At any rate, this is how I've approached the matter for the last two years - If anyone thinks this is off the mark, please let me know. I love getting advice from this forum. Good luck with the 240!
Mast bend helps you control the amount of power you'll get out of the main. Since there is no running backstay (nor is there a Cunningham) on the 240, I don't think you have as much flexibility for depowering by flattening the main as you would on a boat that has those features. If the vang and outhaul on a 240 are already maxed (assuming the main was hauled all the way up - look for the black masking tape near the top of the mast) there is nothing else that I am aware of (short of easing out the main and/or reefing) that you can do with the rigging while underway to depower. In a boat with a running backstay, putting bend in the mast by tightening the back stay will flatten the sail and depower it. I guess the point of all this is that when you are tuning the rigging, you might want to think about the prevailing conditions you are sailing under and put in the amount of prebend for those conditions, i.e., if you constantly sail in heavy wind, then you might want to put more prebend in the mast. Although it will slow you down in lighter air, it will give you more control in heavier air and, in my view, allow you to hold off on reefing just a bit longer. At any rate, this is how I've approached the matter for the last two years - If anyone thinks this is off the mark, please let me know. I love getting advice from this forum. Good luck with the 240!
RE: more rake == flatter sail???
To: J.P. Dyer I guess intuitively I don't see how putting bend in the mast by tightening the back stay will flatten the main out. Seems to me this would yield a shorter distance from the aft end of the boom to the top of the mast, this allowing for the leech (sp?) edge of the main sail (the edge not connected to the boom or mast) to luff more, not flatten more. Clarification please, as I don't ever adjust things all year, just tighten up appropriately in the spring and live with it all season, but I don't race the boat. I did get to crew on an atlantic 30 recently during a race, and the capt did adjust the rake at the dock, I just didn't see which way, and never asked. - Mel 25.5
To: J.P. Dyer I guess intuitively I don't see how putting bend in the mast by tightening the back stay will flatten the main out. Seems to me this would yield a shorter distance from the aft end of the boom to the top of the mast, this allowing for the leech (sp?) edge of the main sail (the edge not connected to the boom or mast) to luff more, not flatten more. Clarification please, as I don't ever adjust things all year, just tighten up appropriately in the spring and live with it all season, but I don't race the boat. I did get to crew on an atlantic 30 recently during a race, and the capt did adjust the rake at the dock, I just didn't see which way, and never asked. - Mel 25.5
Mainsail trim
Underdog, I'm no expert but JP is talking about mast bend not mast rake. When the bend is added to the mast it pulls the luff of the main forward thus reducing draft depth, at the same time vang tension keeps the leech tight making for a very flat mainsail. I have added a cunning ham and lower reef point on my main and run the lines back to the cockpit along with the outhaul making for easy adjustments on those maginal days when you need the drive from the main but do not want to reef. Carl h240 Relentless
Underdog, I'm no expert but JP is talking about mast bend not mast rake. When the bend is added to the mast it pulls the luff of the main forward thus reducing draft depth, at the same time vang tension keeps the leech tight making for a very flat mainsail. I have added a cunning ham and lower reef point on my main and run the lines back to the cockpit along with the outhaul making for easy adjustments on those maginal days when you need the drive from the main but do not want to reef. Carl h240 Relentless
Flat Sail
Underdog, I was talking about bend rather than rake and I think Relentless' explanation is a good one, at least as I understand it, and I'm nothing close to being expert in these matters. Try this, if you have the time and inclination: on a boat with a running backstay, lie down under the boom (hoist the sail in the marina if you can). Have someone tighten the backstay all the way. Watch what happens to the belly of the sail when the backstay is tightened. I bet you'll see it flatten out for the reasons noted by Relentless. I'm heading out tomorrow - the forecast is for some pretty good wind! Can't wait! J. P. Dyer
Underdog, I was talking about bend rather than rake and I think Relentless' explanation is a good one, at least as I understand it, and I'm nothing close to being expert in these matters. Try this, if you have the time and inclination: on a boat with a running backstay, lie down under the boom (hoist the sail in the marina if you can). Have someone tighten the backstay all the way. Watch what happens to the belly of the sail when the backstay is tightened. I bet you'll see it flatten out for the reasons noted by Relentless. I'm heading out tomorrow - the forecast is for some pretty good wind! Can't wait! J. P. Dyer
- Status