The code zero is an additional headsail mounted on a separate furler attached forward of the main head-sail furler. An additional bracket needs to be fabricated to attach this to the stem-head fitting. The sail furls on a rope-luff and is hoisted using the spinnaker halyard. This furling system increases the cost of the sail considerably but the performance benefit for a Maxi 1100 in the right conditions can be quite considerable!
The following advice is provided by Jeremy White – White Sails…
“A proper Code 0 should be constructed from a Laminate not a Spinnaker Nylon as the loads are very high and Spinnaker nylon would soon distort, laminate sails take up allot of space so the sail would really need to be on a furler. A proper Code 0 takes time to set up on the boat so should only be used on quite long legs of the course. A Code 0 can not be tacked so would be of little use if you were short tacking against the tide. In my opinion a proper code 0 has a narrow band of use, unless you are going offshore.
An alternative is a very flat Asymmetric sail, constructed from 2 weights of Spinnaker Nylon.
It will not require the extreme luff tension of a Code 0 and will be used in very light conditions when Standard Spinnakers cannot be flown. This will get the boat moving in an up wind direction. The sail will be launched in a normal Spinnaker bag, and flown from the bow.
Flown from the head-sail furler, this would have wind range of 0-20Knts true, the boat would be much faster out of the Tacks, Faster out of the start line, and would easily make up for the hike in the Rating.