I really love hearing about your personal experiences with this, and I think a lot of other people do too. if it were low power electronics you were powering,

I really love hearing about your personal experiences with this, and I think a lot of other people do too. if it were low power electronics you were powering, I would suggest taking the battery to 14.4v and using some diodes to drop the voltage down a little bit. There would be some power dissipation in the diodes and that would increase with current, so it's probably not a great solution. It might not be that bad to run the motor out of spec a bit. It sounds like you have a good solution. Did you consider putting the lead acid battery in a towable floatation device of some sort?