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Old 16-11-2008, 00:00   #1
TOM
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Bent mast.

I'm just about to purchase a 40 foot yacht ,cutter rigged. The survey came up well except for a slight bend at the top of the mast .When the back stay is released the bend disapears,the surveyor thinks this is a problem associated with cutter rigs ,the broker says it is quite common and nothing to worry about,I have decided to get a rigger to look at it anyway Has any else experienced this problem and should i be concerned ,the boat is otherwise in great condition.

Would appreciate any feedback.

P.S. If anyone recognises the design in the pic I wuld love to hear from them it is 31 years old but looks less then 10 , built in Sydney Australia of 6mm steel {round bilge} called a footloose 40 but I can not find any info on the net.
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Old 16-11-2008, 01:55   #2
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Mast Bend is a major tool used to control Mainsail Shape & Draft. The amount of mast bend depends upon the cut of your mainsail, your point of sail, and the wind speeds, and sea conditions ... etc.

Basically*:
More Mast Bend reduces (flattens) the Mainsail, opens the leech, and moves the draft aft.
Less Mast Bend increases draft, and moves it forward.

If your mast is meant to be bent, as a tool for sail trim, it will likely have an adjustable backstay. Masts that are not designed (static backstay) for the use of mast bend, as a tool for sail trim, often have a forward pre-bend.

* Properly using Mast Bend is a fairly technical subject, so I suggest that you Google:
< mainsail trim >, < rig tuning >, < mast bend >, and < mast pumping >.
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Old 16-11-2008, 07:48   #3
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If the bend is in the fore and aft direction and disappears when you release the backstay, it was designed for sail shape control. If your surveyor thinks its a problem, I think you have a problem with your surveyor...any decent sailboat surveyor should know this.
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Old 16-11-2008, 10:39   #4
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Nice lines....I like the long flush for deck
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Old 16-11-2008, 11:18   #5
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"the surveyor thinks this is a problem associated with cutter rigs "??????????????????

I laughed out loud reading this. Listen to the gents who have answered, no worries.
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Old 16-11-2008, 12:23   #6
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Serious advice

Your surveyor should stick to house sales - get a new one.
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Old 16-11-2008, 13:56   #7
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First I would tend to rely heavily on the advice of the rigger who will be on the spot and can assess the intention of the rig from the mast section and the staying.

Being on a heavy cruising yacht I would assume that the mast is sectioned to stand in straight column rather than be bent to manage sail shape (the in mast furling may also place a limitation on any intention for bend). If meant to bend one would assume that there is tackle or hydraulics at the lower end of the back stay to manage tension in the backstay to set up the bend while sailing - I don't know if that exists, if it does then you have your answer.

If it is not meant to bend, and that would be the most usual on a heavy cruising boat, then my first reaction would be that the inner forestay is set up too tight rather than relying on the (assuming they exist) running backstays to maintain tension. Alternatively, but unlikely, the mast section is undersized to stay in column with the inner forestay properly tensioned.

The tension on the inner forestay can be less than that for the forestay as the sail load causing sagging of the sail luff to leeward is less due to the smaller sail area and its length being shorter.

A good rigger will assess the situation within a couple of minutes.
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Old 16-11-2008, 14:25   #8
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I agree. If the bend goes out when the backstay is released you don't have a survey problem but you still need a good rigger.

As mentioned above, it is really, really important for in-mast furling to be in a straight mast. The number one reason that these rigs jamb is from mast pre-bend. Pre-bend is a rig induced bend in the upper third of the mast which can be very helpful with a regular mainsail to control draft and keep the mast from "pumping" in a seaway. Note that mast "rake" where a straight mast is angled back is not the same as pre-bend. Many boats sail better and are designed for some mast rake but it is sometimes taken out due to incorrect rigging adjustments.

While any good rigger knows this, I would emphasis to him/her that you really want as little pre-bend as possible to minimize the chance of furling problem. A jammed mainsail really ruins your day.

Carl
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Old 16-11-2008, 15:44   #9
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Quote:
Originally Posted by CarlF View Post
I agree. If the bend goes out when the backstay is released you don't have a survey problem but you still need a good rigger.
Carl
Gosh, the last time I let a rigger near my boat it took me an afternoon to fix his 'adjustments'.

This is an area every sailor should become proficient, as there are darn few riggers available when you need one, in the middle of an ocean.
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Old 06-12-2008, 14:41   #10
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MidLandOne is correct.....
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Old 10-12-2008, 16:27   #11
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If the mast straightens out when the backstay is released it ain't bent.
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