The Nassa unit draws very little power, one of the large lantern batteries (The ones with curly sping terminals) should easily power it. On my Leisure 18 I had a mini car battery (Mini in Mini type car) that powered the sounder, I never recharged it during the season and it worked fine.
Oil bath is - Castor Oil, available at ant Chemists in 250ml bottles. Buy two ..... one for the in-hull tube, the other spare for topping up .... lasts for years.
BEFORE fitting the tube, Mr. Muscle Oven-Cleaner gets ALL crud of the hull, then wash / clean away with fresh water .... let dry and then you have a good clean surface to glass your tube to.
As to E/S with battery.... most will run on 9-15V supply, so a small gel-cell alarm rechargeable battery will do nicely... or a small motorcycle / car battery. For true internal battery job .... the older Seafarer LED style has proper provision for 9V lantern battery .... works well - I had one for years !
would be just the ticket. There's at least two operations, one at Bournemouth, which keep them going. Look in PBO classifieds for their addresses, they might have a spare one to sell you.
