Cutter rig staysail often poorly drawn

[MikeJohns]

Something to be aware of

It seems some yacht designers when asked to supply a cutter rig sail plan do not consider the operating slot and design the head far too close to the mast as they would for a single headsail. This is fine if its just a storm jib and operates with a reefed main. Otherwise with a full main the top part of the staysail doesn't move out when the sail is eased and it backwinds the main in the middle of the luff. Needs a clear and largish gap on the sailplan.

The lower part can overlap but the upper should stand well clear.

[Robert Gainer]

Do you have some thoughts on what’s reasonable? To open up the slot you need to drop the head and it looks like you would lose a lot of sail area if you went too far in that direction.
All the best,
Robert Gainer

[MikeJohns]

Robert
A couple of thoughts if you were concerned about sail area........
The inner forestay could be designed to attach further up the mast.
There is a gain in mainsal efficiency if not backwinded
The overlap of the staysail could be increased (unless boomed..another topic)
The overlap of the outer jib could be increased. eg yankee with a slightly lower clew would more than compensate.

As to what is a reasonable slot.. depends on a few factors but perhaps 3 feet for the head to mast clearance on an average 45 footer.

I just wince when I see the stayseal head drawn firmly attached just below the stay termination. Fine if its just for a storm jib but not so good for an inner jib when carrying a full main.

Cheers

[bhnautika]

Mike how about 10% of J down from the mast head for the attachment point (re.Gutelle)

[MikeJohns]

Originally Posted by bhnautika

Mike how about 10% of J down from the mast head for the attachment point (re.Gutelle)

BH
Depends on the stay angle relative to the mast of course but thats a start.

Ive seen people order inner jib/staysails direct from their sail plan only to find they are terribly prone to backwinding the main. Some of the earlier stock plan designers were particularly bad for failing to take this into account and I've seen it recently in study plans from popular designers . I can only presume they have never sailed a cutter rig.

Cheers

[FAST FRED]

Illingworth and Primrose , in their books Offshore and Furthur Offshore were written back when Cutters were not handycapped out of competition.

And their version 50's and 60's of "lightweight hull" is fairly common displacement on cruising hulls today.

The boats they raced were truly seaworthy and converted into excellent short handed offshore cruisers.

They have the absolute best description of cutter rigs and the tradeoffs between foresail , staysail and mainsail required to have them go fast and be really handy.

We copied theit design for the sailplan (after 9 years of racing improvements) for Myth of Malham, and the results have been startiling for a cruising boat with a DL of 333!

We did add full battens to the main to support more roach, but otherwise no changes.

For offshore performance nothing can touch a cutter to about 60 ft..

FAST FRED

[MikeJohns]

Thanks for that Fred

I havn't read either of those, pity the rig has lost popularity, I agree it is a very practical and handy rig I am particularly fond of it myself on big boats.

I think an overlapping staysail is better to have than a boomed job. But it does give another task when changing tacks. What sort of staysails did you design in the Myth sailplan copy? Some of the wishbone booms are used to good effect on staysails but you get better drive from them with a good overlap.

cheers

[FAST FRED]

With modern winches the jib boom is passe.
It can be a killer during any foredeck work and the deck track is another hassle to kill your toes & ankles.

The winches are aranged on out boat so as you tack the fore sail then the staysail are released.

If your'e fast both can be hand tightened enough to keep way in the new heading.

We tack with a numbered push of the autopilot , so no time is spent controlling the boat, just tending the sails.
Release , release , trim ,trim, DONE!

We cruise with an overlaping (not much ) staysail and a set of high cut Yankeys and a forestaysail genoa for the really kight stuff.

Real sails are used , not roll up window shades , that work poorly in every situation but broad beam reach.

We did purchase the large overlaping staysail , but it sees little use , as the area of the genoa is so much higher.

I am always looking for a genoa I could recut to a Quadrilateral Jib, as I think the huge clean luff , great area and lack of area aft would reduce healing when hard on the wind.

I like the concept of the wishboom boom , but in practice on the Main its hard to reef or stow.

The full battens and std boom , slab reefing , works well for us short handed.

Being lazy we have a seperate track and use a "Sweedish Main" instead of a second or third reef while underway.

The Sweedish main is about 1/2 the area of the main but its cut like a tri sail,(sheeted , no boom) just way bigger ,
Nice long luff really works well in 25 to 40K breezes ,going to windward at hull speed .It takes power to climb hills.

A heavy reef makes it suitable as a storm trisail, but a storm staysail controlls the boat better as the mast on a real cutter is 50% lwl aft of the bow.

FAST FRED

[MikeJohns]

Fred
What size boat are you sailing?

I always like the idea of the shape of the quad. headsail too. Never yet sailed with one. Do you need two sheets ?

cheers

[FAST FRED]

Do you need two sheets ?

Yes , but its usually a light weight sail (-14K), so if the sailplan was drawn properly as a cutter , the quad will blow over with no help.

The hard part is designing the lower clew to sheet ONBOARD , rather than behind the boat.

A Big block on the quarter is needed , as well as a fair lead to the "off duty" sheet winch for lower clew controll.

"Sea Gypsy" is 33.3 loa 28 lwl (Jester class for the old OSTAR) 10.3 beam.
The hull is the Lone Gull2 by M. Griffiths expanded from 28 loa to 33.3 loa.4.3 ft draft , inshore FW load.

She is built of Airex with hand layup and Hetron Fire retardant resin to USCG specs for a Subchapter T vessel.
She has a watertight collision bulkhead (CG requirement) and 2 more wt doors and bulkheads for flooding controll.

Ballast is 7000lbs on 16251 lb displacement.
Sail area is 737 wirking with over 1000 for the light stuff.

Downwind there is a doubble roller jib with both luffs attached to the wire.
Two poles are used as developed by Wright Brittin.
Power is the hand startable Volvo Md3B with dual 125A alts , col pump fridge compressor and 2 in clutched Jabsco bilge pump on selectable manifold.6 1/2K at 1600 to 1800 rpm depending on house loads . 3/4 gph fuel burn. 24 gal fuel ,200 water in 6 tanks.

We have cruised the Carib and Bahamas and found her to be quite handy and easy to work.
All the rigging and sail areas were sized so a single handed person (esp my 100lb bride) can hand reef & steer with out calling the "off watch" , me!

The boat has cold plate refrigeration (2 hours of engine time for a 4 day holdover) and central heat ,
a Dickinson Ant- Artic with 7 turn water coil and thermosyphon loup to heat the 2 foward compartments with out electric.

Have weathered -17F one winter in NYC , no electric at the marina and T shirt living inside (but dont stick your head out!).

Sleeps 4 , two foward in doubble with bundeling board , and 2 aft in Concordia bunks.

Full complement of sails , copied from Myth of Malham. with Full battened main . all by Cheoy Lee .

FAST FRED

[Vega]

It seems to be a very nice boat. Can you post a picture? (preferably on the thread about member's boats).