Mast rake angle

Mast rake angle

Postby Erik » Sun May 20, 2018 5:36 pm

To All

I have recently acquired a 33 Cat Ketch #74 built in 1983 and noted that the Mizzen is raked aft. Does anyone know the correct rake angle for both masts.

Thanks

Erik
Erik
 
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Re: Mast rake angle

Postby Castaway » Sun May 20, 2018 6:23 pm

Hi, Erik,

If the masts are nicely centred in the deck apertures – i.e. the partners are even all round – then they are in the proper position. If the boat sits a little down by the stern, that will effectively give them more rake, and the weight of the boom on the topping lift will also bend them aft when the sails are not set.

I don't think there is a requirement for any rake, since the sails are shaped by the tension in the outhaul (if you have the wishbone booms), and the centre of effort is best adjusted using the sheets to balance the effects of the two sails. Any pre-set rake will be irrelevant due to flexing of the masts when under way.

As for Castaway, the masts lean fractionally to port (mizzen) and starboard (main), which I explain is a necessary feature to account for the Coriolis effect when sailing in the Northern hemisphere at high latitudes. That saves me from trying to mould new and more accurately aligned partners.

Regards,

Gerald
Gerald Freshwater,
s/y 'Castaway', (UK F35 cat ketch)
Lerwick Boating Club
Shetland Isles, Scotland
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Re: Mast rake angle

Postby Erik » Sun Jun 03, 2018 2:18 pm

Thanks for your response Gerald

Glad the Coriolis effect is under control up north down here in New Jersey we really don't need to worry about it.

Regards

Erik
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Re: Mast rake angle

Postby Jesse » Sat Jul 07, 2018 7:03 am

Hi Erik,

I have a 21, which is probably a different beast than the 33, but when I set my mast I ended up with a fair amount of back rake. I have been sailing with it for the past year and it sails fine, but I am convinced that if I straitened the mast the boat will hold better in gusts and strong wind. She tends to really round up into the wind, and having back rake can only add to this. Reefing and dumping the main are one way to deal, but I think the boat will sail better without any rake. Im going to restep the mast later this summer.

So my thought is the rake all depends on your boat and your style, but I don't think there is any need for rake in the mast and it is probably best to have none.

Best wishes
Jesse
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