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Ross 780 keel angle


gisywaterboy

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Hi there, does anybody out there know what angle a Ross 780 keel should be relative to the waterline? (What degree of rake it has)

 

I think my keel may be loose fore-aft in the case, causing the keel to have less rake and thus moving the centre of lateral resistance forward, creating bad weather helm.

 

Any help would be much appreciated.

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Hi there, does anybody out there know what angle a Ross 780 keel should be relative to the waterline? (What degree of rake it has)

 

I think my keel may be loose fore-aft in the case, causing the keel to have less rake and thus moving the centre of lateral resistance forward, creating bad weather helm.

 

Any help would be much appreciated.

 

I would think the keel would have to move a lot (FORWARD) to influence weather helm.

 

How much is it moving? the box should not allow to much

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I'm not sure how much it is moving. I will swim under and put an adjustable level on it this weekend to see what angle it is sitting relative to the case.

 

I have played around with mast rake until she sails ballanced but the mast is now almost upright (other R780s are balanced with a fair amount of rake) and she does not want to sail upwind. (lacks forward pull).

 

The weather helm occurs at all points of sail, except flat running, even with a kite up, which can get a bit interesting.

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if the keel is moving, in my experience (on a noelex 30) you'd feel it. It won't move smoothly, it will load up and jump with a thud, even if it is only a mm or 2. The noelex would do that if the keel was not fully down...

 

Also in my experience, these are the likely things to cause weather helm

 

Rig tuning, esp rake.

Old sails (main) with draft moved aft

rudder not fully down

leech tension control on the main

Sail trim, sail trim, sail trim......

 

You need to be absolutely certain that none of these is an issue before looking at keel problems. The keel is locking right down into the keel box, right?

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I modified a 780 ( Thirsty Work ) with some success. Without going into too much detail I actually fitted a fixed keel. one of my own designs which had the leading edge at right angles to the water line. Straight up and down. The trailing edge tapered forward at the bottom. I increased the rig but kept the C of E in the same place. The new balanced spade rudder was in the same place but I did extend the hull by 600mm.

 

I suggest you check a bit of other stuff before worrying about the keel angle. I would start with trim.

These little boats were one of Ross's best and box well above their weight even if left standard.

Good luck.

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