mast rake

[rob.lovelace]

I can't seem to find any info on this and I'm sure Ive asked before, anyway I'll
ask again.
What is ballpark mast rake on a top hat? I measured mine just before dropping the mast yesterday and had about 85mm at the base, which I figure is about half a degree. From what I read rake should be between 1 degree on a cruising boat to up to 5 degrees on some racers. I was thinking of moving it forward as my boat has weather helm that can be rather savage when I'm over powered. But after measuring the rake I'm now not sure about moving it forward any more. I seem to recall being told about 100mm was standard.
all feedback as always appreciated

Rob
Sundowner
Westernport
Victoria

[Phillip]

Rob,

This is one of those questions we all get to ask at some time. Seaka has a rake, or rather a bend of almost the full width of the mast [at the top] towards the stern. Now this is not an extreme rake, as I have seen some yachts [not Top Hats] with what looks like ridiculus bends of some 500mm.

Seaka was set up for racing [in Pittwater] and I have maintained that set up.
I do not have much weather helm, in fact I am only aware of it when things get to a stage when I should be reducing sail.

I did put on a tensioning arrangement on the backstay, but removed it as I could never determine if there was any diference when I put the tension on.

Hope this helps.

Phillip

[rob.lovelace]

hmmm. not really Phillip, I also had a substantial mast bend on Sundowner, this being achieved by tension on the forward lowers. It is after I have removed the bend that I can then measure the rake (with a straight stick) using a string line that I ran up the halyard with a lump of lead on the bottom. K also have a backstay tensioner (one that squeezes the lower part together ) I'll tighten that up to windward to put tension on the head stay and help flatten the genoa some and help her point higher.

Is the bottom of the mast dead in line with the upper shrouds? Maybe I can move the whole stick forward an inch? This is my first go at setting up the rig so I don't expect to nail it first time.

[Tales]

Mast rake on the drawing for the Mk II and III shows a range of 0 to 100mm.

I think there was a copy on this site but can't seem to find it now.

Can send you a copy if you like.

Cheers,

Tom

[storm petrel]

0 to100mm is right. Perhaps the weather helm is caused by something else? How much draft is in the main? I find flattening the main and using the traveller rather than the sheet to trim the main allows me to pretty much negate the weather helm (At least until the gunwale goes under continually to remind me it is time to reef)

Cheers,
Mark

[Phillip]

Rob,

When looking for your rudder information came across this:

storm petrel » Mon Jun 14, 2010 9:44 am
Between zero and 200mm (8") according to the original sail plan for the Mk11.
Cheers,
Mark


Phillip.

[Dolphin]

G'Day Phillip and Rod,
Here is the info from the original sales drawings. Straight from the horse's mouth.

Detail at the top of the mast.

Sail Plan Overall

Sail Plana.jpg (23.79 KiB) Viewed 4644 times

Best regards, Greg

[storm petrel]

Oops, yes I have the original drawing also and it is 0 - 200mm. Don't know what I was thinking with the post above.

Cheers,
Mark
Storm Petrel

[rob.lovelace]

well I had 85mm so I'll give 50mm a go and see how that feels

[storm petrel]

I will be interested to hear if you can notice less weather helm after this change. I expect you will need to make a bigger change than this to really notice it, but would be happy to be proved wrong.