Bulb upward cant

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cjepearson
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Joined: Thu Feb 15, 2018 9:58 am
First Name: Chris
Last name: EsdalePearson

Bulb upward cant

Post by cjepearson » Tue Jan 29, 2019 3:13 pm

Good day,
Does anyone have an explanation as to why the bulb on an IOM should be canted up at the forward end +/- 2 degrees?
How critical is it, and how do you measure it? I made a template of the fin and bulb, and measured 2degrees over the length of the bulb, then measured the "lift". Adjustments were made with flattened crimps in the bulb slot. All a bit crude.

Dave Alston
Posts: 224
Joined: Fri Dec 06, 2013 10:04 pm
First Name: David
Last name: Alston

Re: Bulb upward cant

Post by Dave Alston » Wed Jan 30, 2019 11:13 am

The boat tends to go bow down as the boat is driven forward.

The amount of up offset required varies from design to design and sail setting.

In other words there is NO magic offset amount . It is a comprise. However it is not likely to have a profound effect for most skippers, but it is that 0.01percent you might be looking for.

Interestingly the shape of leading edge of the bulb is probably more important

Helps ?

cjepearson
Posts: 3
Joined: Thu Feb 15, 2018 9:58 am
First Name: Chris
Last name: EsdalePearson

Re: Bulb upward cant

Post by cjepearson » Fri Feb 01, 2019 11:00 am

Thank you, David. I had the misfortune to hit something in the water, when the water level was very low in the summer, and the bolt on the fin was bent. I am trying to reset the bulb to it factory setting.

Dave Alston
Posts: 224
Joined: Fri Dec 06, 2013 10:04 pm
First Name: David
Last name: Alston

Re: Bulb upward cant

Post by Dave Alston » Sat Feb 02, 2019 4:42 pm

So have you figured out how to do this

Lester Gilbert
Posts: 20
Joined: Wed Dec 04, 2013 1:36 pm

Re: Bulb upward cant

Post by Lester Gilbert » Tue Feb 19, 2019 9:18 pm

An early page of mine might be interesting.

http://www.onemetre.net/Design/Bulbcant/BulbCant.htm

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