Rigging Spinnaker Sheets

There are two options, one line per side serving as a guy or a sheet depending on the which tack you are on (often the default choice racing with smallish sails) or a sheet and a guy either side (The seaman's option).

Single Sheet

A single sheet each side is rigged from, or close to, each quarter with a barber hauler / "Tweaker" to pull the windward one down to the toe rail at around the boats maximum beam (B-Max) (or with a small sail just a simple hook there to hold it down) this saves weight on the spinnaker and two relatively expensive sets of fittings and bits of rope that will clutter up the cockpit. On boats with very wide transoms close to B-Max, it may not be necessary to have the guy coming from so far forward to get a good angle on to the tack side, but keep reading. 

On a crewed racing boat this method will generally be preferred even with quite large sails (Back in the day I ran the foredeck on a one tonner c40ft boat with single sheets). Single handed they are usually OK with small sails, but gybing becomes trickier with bigger sails in anything other than light winds. 

The problem is getting the pole clipped back onto the mast during a gybe when there is significant pressure on the windward sheet - there is a real risk of getting the end of the pole in the face or through the mainsail if you are not careful. A secondary issue may be getting the "Tweaker" to a cleat without it going over the jack stay, that can usually be resolved by having the block attached to the toe rail or u-Bolt with a snap shackle and store it inboard.

The spinnaker gear on Green Dragon a rather good 30ft 1/2 tonner😉.

A few things to note about Green Dragon's fit back in the late 70's:

• The spinnaker pole (the length of which was limited by the IOR rules to <= J) should ideally be horizontal to project as far forward as possible but the mast, which had an extremely small section, could not support a track for the inboard end so we had to live with it.
• The pole it very light weight even for the small sails (IIRC we had  a very light full sized "floater", a medium weight tri-radial and a heavy weather spinnaker) so it has bridles top and bottom, always a good idea to reduce the strain on the pole.
• As was common at the time, the pole uphaul, like the halyards, was wire with a rope tail, ropes were not as strong back then and they stretched, now rope can be used although there is a bit more windage.
• With the small spinnaker inherent to the 5/6th rig (and me, running the foredeck, being a lot younger and fitter than I am now!) single sheets with “tweakers” were used although here we had the jockey pole fitted which is tied down to a stanchion base so were not using the "tweaker".
• A jockey pole is an excellent aid when reaching with a symmetrical and stops the pole bashing against the headsail foil or furled genoa, but they are expensive, about the same as the spinnaker pole - c £500 for an A9m, and I have an asymmetrical sail for reaching so I don't have one.
• The pole down haul had a two part purchase and went back to a cam cleat rather than a winch.

Lazy Sheet & Guy

I found that with Sancerre’s 60 square metre spinnaker it was difficult to get the pole back onto the mast when gybing with tweakers with no crew to trim or helmsman to help, so I went back to the traditional method with a sheet and a guy each side.

Another advantage of two lines is that one line can be used to relieve the pressure on the other if there is a jam or other problem, what I meant in the opening sentence as this being the seaman's solution. 

Its rarely used these days but a dip pole gybe (that is safer for the foredeck hand  in rough weather)  requires dual lines as would a twin pole gybe (even more secure) but that would only be used on quite a big or old boat.

One of my spinnaker sheets, that I had just remade with a new shackle.

The lazy sheet is over the pole ready for the pole
to drop away during a gybe. Note that in a
very light wind I had not rigged the pole
down haul and the lower bridle is not loaded.

The sheets attach to the sail with a snap shackle and it goes right aft before being taken to a winch. The Guy attaches to a stainless steel ring spliced onto the sheet with the snap shackle and goes to the toe rail at the point of maximum beam (B-Max) and usually a bit forward of the cockpit if the beam is constant over a long distance. The lazy guy (the one not being used) can be unclipped if its weighting the clew down but in stronger winds it is best left on as it can then be hard to reattach and if not using a snuffer it can be used to haul in the spinnaker when dropping.

To gybe pressure on the guy can be eased by heaving in on the lazy sheet, this will make it easier to get the pole of of the mast but can make it trickier to release the guy from the pole. 

The pole comes off the mast and the outboard plunger pulled to drop the pole away from the guy. The ex lazy sheet, that you remembered to grab hold of at the start of the manoeuvre, is clipped onto the ex mast end of the pole and supported by the pole up haul (that goes to the centre of the pole) is pushed out under the old active soon to be lazy sheet and the pole reattached to the mast.

Crewed the spinnaker gybe can be done in-sync with gybing the main and done through an acute angle, single or short handed gybe from and too a very broad reach say 170 degrees apparent and gybe the main first, with care the spinnaker will keep flying with the pole on the "wrong" side for much longer than you might think. 

General

For ease of handling and reduced stretch guys are best larger than the sheet, they don’t do through the pole jaw, so the thick splice is not an issue.  I use 12mm for the guy (red marker to port, green to starboard) and 10mm for the sheet.

For very light winds take a sheet =< 6mm with a lightweight snap shackle (mine are plastic), the lack of weight will allow a spinnaker or cruising chute  to set much better but don't delay in reverting to the larger line if the wind increases.

The normal rule of thumb is for guys for symmetrical spinnakers and sheets for all downwind sails that are to be gybed should be twice the length of the boat (Cruising chutes can be used with a single sheet 1.5 times the length of the boat but it can’t then be gybed). I prefer the sheets for a symmetrical (that will be also used for an A-Sale) to be a bit longer to be on the safe side and to allow me to remake the business end when it gets worn or the shackle needs replacing..

Ensure that the sheet will run through the end fitting of the pole, including the splice. On mine 10mm for the sheet works fine, the splice on a 12mm line would stick.

When close reaching with the genoa, the sheet will be against the guard rails the spinnaker guy, or sheet plus "tweaker", can be temporary clipped on used as a sheet hopefully improving the sheeting angle and certainly reducing chafe on the sheet and strain on the guardrails. Sheets should also be fine for a cruising chute.