Echo sounder with self contained battery

Any ideas as to what is best? I have no ship supply.Also the transducer must be fitted in an oil bath not thro hull;

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 !

I used a 9V PP3 with the Nasa Target sounder and it lasted all season.

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.

Hope this helps