Shaft Length Guide

Selecting the correct model for your boat is the first step, then shaft length and power are the next two critical factors to ensure you get the best performance out of your Haswing trolling motor.

Shaft length is particularly important for bow mount models such as the Cayman series, as bow deck to water height varies depending on the type of boat you will be mounting the motor on. Obviously on a low-sided open fishing boat that distance will be less than a 7.0M deep-V ocean going fishing boat.

A reliable benchmark is to measure the distance from the front of the bow deck where the motor will be positioned to the waterline, then add 500mm in order to ascertain the correct or even minimum shaft length. Though if you regularly fish in rough water, you could add another 125mm to that overall shaft length to account for the boat bobbing up and down in the rough water. You of course can adjust the required shaft length to suit the conditions by adjusting the ‘height collar’ on the shaft. Better to have extra length available when needed than insufficient.    

How to Measure Shaft Length

Measuring the shaft length is an easy task, as shown on the diagram below you actually measure the shaft from under the trolling motor head to the top of the propeller housing.

Bow Mount Guide


0-254mm (10”)

254-560mm (16”-22”)

560-760mm (22”-30”)

760mm +  (60” +)


915mm (36”)

1070mm (42”)

11220-1370mm (48”-54”)

1370-1524 (54”-60”)

Transom Mount Guide


0-254mm (10”)

4-380mm (10”-15”)

380-508mm (15”-20”)

508-625mm (20”-25”)


760mm (30”)

915mm (36”)

1066mm (42”)

1218mm (48”)

REMEMBER –  there should be at least 300mm (12”) from the waterline to the top of the motor under the water to prevent cavitation in choppy conditions.

A guide to run times

Calculating the Run Time of Motor

Almost every customer asks “How long can I expect the motor to run for on a single battery charge?”. This actually depends on a number of factors such as the weather and water conditions, how fast you run the motor, the weight of the boat and so on. But there are two major things that determine the run-time: the amperage capacity of the battery and the amperage draw rate of the motor. Fairly simple science really!

Amperage Hour Rating – Every battery whether lead acid, gel cell or lithium has an amperage rating ie 105Ah (amperage hours) which is an indication of how long a battery can supply a continual amperage. So a battery with a larger amperage rating will last longer than a smaller rated battery. A simple guide is as follows, a 105Ah battery is theoretically capable of supplying 25 amps of power for 4.2 hours (25 amps x 4.2 hrs = 105 amp hours) before it will become flat and require recharging. But if you only draw 10 amps of power then you could expect to get up to 10.5 hours of running time.

Amperage Draw of the Motor – Now compute the estimated motor run-time based on amperage draw. The actual amperage draw of the motor is how much amperage (or current) the motor draws at a particular speed. The slower the speed you operate the motor, the lower the amperage being used. Conversely, if the run the motor at full speed, the higher the amperage draw rate and the shorter the run time will be. We recommend 105 Ah plus battery for most of the Haswing motors for a 12V model, whereas a 24V requires two of these or 1 x 24V InfinitiPower lithium and a 36V model requires 3 x 105Ah deep cycle batteries or 1 x 36V InfinitiPower lithium.

Variable speed motors (vs fixed speed motors) will generally provide longer running times.

Extending Battery Life and Running Time – It is best to recharge an AGM battery before it is fully depleted of charge, because by fully depleting the charge regularly it can shorten the life span of the battery. Whereas a lithium battery has a BMS (battery management system) that switches the battery cells off when it reaches maximum Depth of Discharge, thus protecting the cells. And when the battery is not in use, it is a good idea to trickle charge the battery with a suitable charger. Doing these things can extend the battery life and the running time on the water and enable you to get the most out of your Haswing trolling motor.

How much thrust best suits your boat?

Matching Motor Thrust for Your Boat

A number of factors determine which model Haswing trolling motor is best suited to your boat such as boat weight, length and type of boat. Some boats have a primary petrol motor to propel the boat but an electric bow mount trolling motor provides for quiet motoring when fishing and for ‘anchoring’ the boat without having to actually drop an anchor and possibly scarring the fish. Or the electric trolling motor may be the primary propulsion method and mounted to the transom such as an inflatable tender, small tinnie or kayak.

Fishing conditions also play a big part as to which model to buy. If you fish on lakes where there is no current a lower thrust model would do the job, whereas if you want to ‘anchor’ in a river or a channel against the current, as larger capacity model will be better suited to the task. Typically an 80lbs thrust 24V motor which requires two 12V batteries or 1 x 24V lithium battery to provide significantly longer running time compared to say a 12v 40lbs thrust model that may have to work harder and hence draw more current to achieve the same result. A lithium battery will typically provide more power and much longer runs times compared to AGM batteries.

General Thrust Guidelines

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