Spinnaker Size

[Trident]

My boat is a Prout Quasar 50. She is 15m with 14m WLL and about a 12:1 beam to length hull ratio. Her cruising weight is 9T and light ships about 7.5T (after much work to bring it down)

She has a 16m mast, stepped 1m above deck level so I can run about an 18m luff length on the spinnaker.

The original brochure of sail plan (from 40 years ago and a now long defunct company) says the Spinnaker size is 205M sq - or 2200 sq ft in imperial.

This means a 13m foot length for an asymmetrical - does that seem right? How big is too big ? Any cat owners have figures for similar sized boats? My current spinnaker has about a 16m mid luff length and a 9.5m foot which comes out a lot smaller...

 

[Daydream believer]

Ask the sailmaker, if you are going to buy a new sail. It depends on how the sail is going to be used & set. ie will the tack be adjustable & flown high, or fixed point.
If the asym is set with a straight luff, the length will be shorter than one designed to be set so it swings round to windward with a large roach in it; thus making down wind more efficient, but not so good when the wind swings round.

 

[B27]

How big are the white sails?
How do you feel about the current kite?
Are you aimong for one all purpose kite, or do you want a big kite for very light air?

Do you want to reach with it, or are you looking for good VMG downwind?
Do you want to sail close to DDW e.g. to keep in a channel or are you happy gybing about to keep some apparent wind?

 

[Trident]

How big are the white sails?
How do you feel about the current kite?
Are you aimong for one all purpose kite, or do you want a big kite for very light air?

Do you want to reach with it, or are you looking for good VMG downwind?
Do you want to sail close to DDW e.g. to keep in a channel or are you happy gybing about to keep some apparent wind?

The main is a large roach laminate that is slightly over size but works well if I did gybe for the backstays - 35m is the spec and I guess this is about 40

The current kite is find in 8 knots plus but a bit weak below that so I'm looking for a real light airs sail - perhaps 4-12 knots that will run 110- 160ish - VMG is the thing with cats but sometimes getting close to DDW is necessary - the current one will work DDW quite well when the tack is on the windward bow cleat.

I'm just trying to find out if the recommended size is realistic as modern cats of 60 feet plus recommend smaller spinnakers. It may be the new trend to 3 wire rigs that make using big kites more risky or it may simply be that Prout mis-printed years ago and there is no one left to say different . My current one seems undersized but gave us 14 knots in 15 knots apparent last week on about 120 degrees (with a kick from the tide of maybe a knot) but going to the specified size is up about 45% on what we have now!