Hi Judith
This can be folded down, but I tend to only drop the top sail and fold in the bow sprit as it fits in my car fine like that.
The easiest method I use for a drop down mast I listed elsewhere once before but cant find it on here at the moment.
Basically
1. Fit a wooden block support at the bottom of the hull on the inside, with a bit of piping (copper tube or similar) large enough for the mast to fit into snugly but not rigid.
2. Into the piping place a spring with a wood cap on top of it to give a springy tension. It also pays to fit a pin through the pipe just above the cap to use as a locator
3. Design the main mast length so that it fits down onto this spring cap.
4. Step cut the mast about an inch to inch and a half, or so above deck level.
5. Put another piece of piping/tube through the decking to support the lower portion of mast - only needs to protrude enough to help support and keep water out - usually about 1/2 inch works.
6. Cut a 1/2 inch deep notch in the bottom of the lower mast, this then locates over the pin in the spring bit - if you fit together you will see how you gain movement of the lower portion of mast by depressing it.
7. All that remains is to have a piece of pipe or similar to fit over the lower bit of mast where it comes through the deck and also wide enough to go over the pipe going through the decking, and high enough to go over the top bit of the mast where it is step cut to hold the two bits of mast together. Usually dependent on where you cut the step this need not be more than two inches long.
8. A removeable pin through this bit of pipe and into / through the main mast holds firmly in place.
9. To fold down - remove the pin, slide the outer pipe upwards and tilt the top portion of mast at the step joint. Ensure you have enough movement in your rigging to allow it all to fold down.
Hope this helps
Andrew