If your boat's outboard motor or engine does not start it may not be the battery, instead the battery isolation switch.
Ultrasonic Antifouling is viewed by the boating fraternity as either hocus pocus or as a cost effective antifouling solution. This review will hopefully dispel the myths and give some clarity to the long term benefits.
Most tests we read are performed after 12 months or less, which is the normal period between antifouling. They all show a cleaner than normal hull which is expected. But what happens when we extend this period.