You need to fit a simple stabiliser-such as the trawlers use. They use a frame fitted to the mast
with a couple of aluminum
pipes at each end going a half metre or so into the water
, with about two square metres of aluminium plate welded to the ends of each pipe so that the pipe is perpebdicular to the centre of the plate.. Temporarily one could lash the frame, such as an old aluminium ladder, or something more substantial fabricated to suit, to the mast
, but if one is to spend time living aboard
, it might be better to fit permanently some sort of fitting to the mast so the purpose built girder frames can be just clipped into place and stayed fore and aft.
This will settle the vessel--it will still rock--but only gently. The frames when sailing can be removed and lashed to the deck
stanchions. They need to protrude a couple of metres at least from the vessel on each side when in use.
Now--for a quickie, swing the boom out as far as it will go with a bucket of water fastened to a chain at the end the end so that the bucket lies just a few inches below the surface.
Use a preventer fore and aft to stop the boom swinging around.