Motor upgrades

The Current Engine #

The boat is currently powered by a 54lb thrust long shaft WaterSnake electric outboard. At max power it uses ~40 amps @ 12v (~0.5kW) and can run for 1 hour and 20 minutes on the 138Ah gel battery.

The motor can push the boat at 2 knots maximum in no wind at slack tide. This is not enough when either the tide or wind is against you and does not allow, for example, getting under the bridges against the tide or picking up a mooring against the wind.

Upgrade Options #

From cheapest on up.

Larger 12v Motor Only ($755) #

The maximum thrust a 12v system allows is something like a 70lb brushless motor. This ~30% increase is not great enough to overcome the present limitations and so a move to 24v is needed.

Turns out after buying and doing a river trial run I'm using 20% more electricity but getting at least 50% more power and water speed. I got 3.6 knots one way and 2.5 knots the other way. Theoretical hull speed is 6 knots but practically it's about 5 knots - so it still can't get me up to hull speed but I feel confident going under the bridges now. It'll be tested out this Saturday for the Garden island run.

The option of dual motors (below) using my previous 54lb motor still exists and I'll try that route next if I feel I still need more power.

Dual motors ($829) #

• another 12 v 54lb Watersnake ($289 Anaconda)
• extra cable and plugs ($~$150)
• extra combined motor power switch ($70)
• extra circuit breaker ($70)
• modified motor mount and bolts ($50)

Larger 24v 5hp equivalent motor ($1755) #

• Haswing Protruar 5.0 Brushless Motor 160lbs Thrust 24V - 39" Shaft Electric Motor (max 105A ~2.5kW -5hp equivalent) ($1,399.00 )
• 5m twin core tinned 2 AWG ($230 )
• 2 x 120A Anderson plugs ($44 )
• 2 x waterproof boot (already acquired)
• Blue Sea 7188 120A 285 Series Circuit Breaker - Surface Mount ($82)

+ Extra battery ($1755 + $300 = $2055) #

• existing charger
• Kings 12V 138Ah Deep Cycle Battery ($248)
• wire and terminals ($50)

+ Upgraded batteries ($1755 + $708 = $2463) #

• 2 x Kings 12V 100Ah Deep Cycle Lithium LiFePO4 Battery ($578)
• Victron SmartSolar MPPT 75/15 ($80)
• wire and terminals ($50)