I only have two winches on board. Do I really need a second set to fly the spin?
You don't need extra winches (depending on where your current winches is situated).
If you furl take down the head sail before setting the asymmetric you free up the winches.
Article with illustration
Rigging the Asymmetrical Spinnaker
Some useful Google searches
rigging asymmetric spinnaker
https://www.google.no/webhp?sourcei...spv=2&ie=UTF-8#q=rigging asymmetric spinnaker
sailing with asymmetrical spinnaker
https://www.google.no/webhp?sourcei...e=UTF-8#q=sailing with asymmetrical spinnaker
You need one spinnaker sheet block on each side - placed far aft on both sides, hopefully you get a fair lead to the existing winches.
I prefer adjustable tack attachment, but it will also work with a fixed tack.
You should be able to do this with a two persons on the boat
helm & foredeck
The trick with setting is to make 110% sure that everything is set correct before hoist.
-Sail stuffed in the bag with all corners available, no twist in the sail
-All lines lead correctly
-Always have the main set, you use it to blanket the asymetric.
1. Attach and adjust tack
2. Attach hakyard and sheet's
3. Steer with the wind on the opposite side to what you are hoisting relative 140/160 degrees
4. Helm put the sheet on the winch ready to haul in
5. Ready to hoist
6. Foredeck hoist the sail (don't sheet in before it is all up)
7. Sail set, sheet in
8. Helm haul in on the sheet until the sail is catching the wind
9. Foredeck take the sheet.
Taking it down,
There are several ways to do it, if you have a loose footed main the letter box drop is good (if not take under the boom)
1. Take the lazy sheet between the boom and the sail.
2. Steer a course where the main blanket the asymetric
3. Let go the tack (blow the tack)
4. Start pulling the lazy sheet and pull the sail through the letter box opening, stuff the sail down the main hatch.
5. Let the hallyard go out fast, make sure the end is secured, keep pulling the sail down.