For your motor which has a peak draw of 56 amps, you should be using a trolling motor connector that is rated for at least 60 amps.
You should also be using a breaker that is bolted to your battery that is a 60 amp breaker.
The wire that runs from your battery should be 6 gauge wire.
Here is a recent post of a wonderful connector that many of us have just discovered:
This connector has a nice high current rating, will handle 6 gauge wires, has a bolt together feature to keep the connector in the socket and has a right angle outlet so that the trolling motor wires do down the front of the bulk head rather than sticking out and getting in the way.
Minnkota and others sell the 60 amp breaker. Use a piece of brass with appropriate sized holes drilled into the brass strap to bolt on the battery, and then bolt the circuit breaker to the brass strap. Finally, bolt the ring holding the 6 gauge battery wire to the output of the circuit breaker. By having the breaker bolted directly to the battery, you will be protecting all of the wiring to the motor in case of a short anywhere from the battery to the motor.
It is quite likely that your boat will not be wired with 6 gauge wire. If that is the case, be prepared to pull out the old wire and use that wire to pull in a new pair of 6 gauge wire. Also, have a swaging tool on hand so that you can put appropriate size rings on the ends of the 6 gauge wire to connect to batteries or to the trolling motor connectors.
If at all possible put only group 31 batteries in your boat. i.e. 1 group 31 battery for your motor and electronics and two more group 31 batteries for your trolling motor battery.
Also, be sure to carry along a short pair of jumper wires in your boat, so that if your main starting battery gets discharged for any reason; you will be able to start your motor by using the jumpers to jumper one of your trolling motor batteries to your starting battery.
Good luck and enjoy your new rig.