Notifications

Clear all

genaker dimensions? - SL1, SL2, SF, SMG

F18 Forum

Last Post by anton 15 years ago

9 Posts

4 Users

0 Reactions

4,952 Views

RSS

vayu

(@vayu)

Posts: 4

Member

Topic starter

[#28213]

I am looking for typical dimmension for genaker 21m2 formula 18 class. SL1, SL2, SF, SMG parameters. I need it to order sail at sail makers. Anyone knows it? Thanks.

Posted : July 15, 2011 5:38 am

david.ingram

(@david.ingram)

Posts: 3879

Captain Registered

The SL1, SL2 and SF are not restricted. Only the SMG has a minimum, where SMG > 75% of SF ;

Calculation of the spinnaker area CSPI :

CSPI = SF x (SL1 + SL2)/4 + [(SMG – SF/2) x 2/3 x (SL1 + SL2)/2]

Below is a sample measurement:

SL1 - 8.596m
SL2 - 7.7m
SF - 3.684m
SMG - 2.8m

Remember, all the measurements can vary as long as the total area is <= 21m2 for the large spin and 19m2 for the small spin. Not every F18 has the same tack, hoist and sheeting location there are small variations and I would expect the sail maker to be aware of those variations so they can cut the sail correctly for your boat.

There is a max hoist height of 8150 mm. Make sure your sail maker is aware of the limit. This measurement is from the spin halyard max up point to the bottom of the mast extrusion.

Please refer to the line drawings in the class rules. You can get a copy here: http://www.naf18.com

Posted : July 15, 2011 8:12 am

F-18 5150

(@hobie18rich)

Posts: 1343

Member

For what boat?

Posted : July 15, 2011 5:07 pm

vayu

(@vayu)

Posts: 4

Member

Topic starter

Thanks

I will check tack, hoist and sheeting location.

I know the SMG>75% of SF restriction. Anyway it gives some possibilities of adjusting sail flatness I think. I wondered if there is an optimal combination of spinnaker measurments values for f18 or just individual cases.

In the sample measurment above SMG/SF is 76%, so very close to 75%. I think it makes the sail as flat as possible according to f18 rules.

-----------------------
lukasz.gawlas@gmail.com

Posted : July 16, 2011 6:49 am

vayu

(@vayu)

Posts: 4

Member

Topic starter

it is nacra inter 18

-----------------------
lukasz.gawlas@gmail.com

Posted : July 16, 2011 6:51 am

F-18 5150

(@hobie18rich)

Posts: 1343

Member

I don't have any measurements for the inter 18 sorry. Is that boat F-18 legal? wasn't there a problem with that boat not making the rule any more?

Posted : July 16, 2011 11:54 pm

vayu

(@vayu)

Posts: 4

Member

Topic starter

Well... With an alu mast it schould be legal. Anyway it is an old design and I doubt if anybody uses it in F18 races. I dont. I am still learning, thats why I am asking about spinnaker dimmensions and its flattnes.

http://www.ukhalsey.com/LearningCenter/encyclopedia/encyclopedia4d.asp

Any other F-18 boat spinnaker measurments will be welcome <img src="<>/smile.gif" alt="smile" title="smile" height="15" width="15" />
I just want to know if it is as flat as hell or not.

Thanks

-----------------------
lukasz.gawlas@gmail.com

Posted : July 17, 2011 2:20 am

F-18 5150

(@hobie18rich)

Posts: 1343

Member