Scott
You mentioned you are nervous of crossing water which is understandable.
Flying is all about risk management and unless you are at an altitude where you can glide to land if you loose the engine you are coming down into the sea!
You can minimize those risks by choosing dead calm days for your trip and not days where harmless looking white caps at 3000 feet are in fact 30 foot waves close too!
The chances of loosing the engine totally are small but there is a chance especially with piston engines so that is a risk you have to accept and take!
Do not go at the end of the day when daylight is limited in event of a search and rescue.
Make sure you are talking to someone?
Maybe consider going up the coast to Blackpool and crossing there which is shorter.
Consider life rafts and jackets ! some would even propose immersion suits as you will not survive for hours in the sea.
At the end of the day life holds many risks there is a risk you have to accept it or not fly single engine piston low level over water.
Pace