A saltwater trolling motor has to carry out under relatively extreme conditions therefore it is important to select one that will be capable of keeping your boat on course and not rot away.
The very first factor to consider of any angler who is in the market for a new or used saltwater trolling motor is will it hold up against the destructive result of the water, a fairly obvious issue however there are still lots of folks who will drop a freshwater motor in the sea and grumble bitterly when it begins to rust saltwater trolling motors.
When trying to find your next motor ensure it is created for the kind of water you are going to be trolling in. A minimum requirement need to be marine grade construction, this consists of all parts of the motor from the prop up. The seals, joints and control all equipment has to be developed for purpose, saltwater will get into anything that is not properly designed to manage it.
Another aspect to be familiar with is the power output of your motor, tidal water is usually more dynamic than state a freshwater lake, this will put additional loads on the motor simply to keep the boat moving forward in a straight line never mind steering versus the ebb and flow of the currents.
A general bench mark for the power required for a trolling motor is 1lb of thrust for each 40lbs of load. The load is the overall weight of your boat consisting of everything that you have actually stowed on it, a safe alternative is to add the weight of the boat to the optimum payload and divide by 40, this will give you a minimum figure for the thrust needed.
Once you have a figure for the thrust needed the next step is to work out how long the shaft of the motor needs to be. This is affected by where you are going to have the motor, a bow installed trolling motor will require a longer shaft than a transom mounted one. To get the length of shaft do a little bit of easy math, determine the range from the mounting point on the boat to the water line, to this number add 15 inches (depth of the motor plus allowance for choppy water) then about a foot to make it comfortable for guiding whilst standing.
If you have a saltwater trolling motor with a foot pedal the allowance for standing up can be overlooked.
With the exception of engine installed trolling motors it is constantly advised to stow the unit if you are using another engine, say, an outboard. This is because your trolling motor will trigger a drag result thus wasting gas as well as since the shaft of the trolling motor may break under the pressure.