Sail Power Technologies

Marine Hydrogenerator Performance

Clean, Silent Power from Your Boat's Motion

Power Output at Cruising Speeds
See how much electricity your hydrogenerator produces as your boat moves through the water. Choose the right propeller for your typical sailing conditions.

💡 What Does This Power Mean for You?

At 5 Knots

145W

Powers your navigation lights, instruments, and charges your phone whilst coastal cruising

At 7 Knots

380W

Runs your autopilot, refrigeration, and keeps batteries topped up on passage

At 9 Knots

380W

Maximum continuous output - generates more energy than you can use in most situations

Daily Energy Production
Watch your batteries stay charged without running the engine. These figures show what you'll generate during a full day of sailing.
Choose Your Propeller
Your hydrogenerator comes with two interchangeable propellers. Simply choose the one that matches your planned sailing conditions. Changing takes just 10 minutes.
Sailing Conditions Best Propeller Typical Power Output Why It Works
Coastal cruising
4-7 knots		 320mm Low Speed 145-380 watts Larger propeller extracts maximum energy at comfortable cruising speeds
Light wind sailing
3-6 knots		 320mm Low Speed 75-255 watts Still produces useful power when boat speed drops
Brisk passages
7-9 knots		 260mm High Speed 260-380 watts Smaller propeller creates less drag whilst maintaining full power output
Fast sailing
9-11 knots		 260mm High Speed 380 watts (maximum) Minimises drag penalty - your boat stays fast whilst batteries charge
Efficiency: Getting More from Less Drag
The clever bit: by switching propellers at 7.5 knots, you maintain maximum power generation whilst minimising the drag that slows your boat down.

âš¡ Real-World Benefits

Annual Savings

$475

Value of electricity generated plus reduced engine running (based on 1,000 hours sailing per year at 6 knots average)

Payback Period

3-5 years

System pays for itself through electricity savings and extended battery life

Build Options

3 Ways

DIY from plans, assemble from kit, or order factory-made units

Typical Cruising Scenarios
Here's what you can expect during common sailing situations. Notice how the hydrogenerator keeps working around the clock.
Scenario Duration Average Speed Energy Generated What This Powers
Day sail
Light winds		 8 hours 5 knots 1.2 kWh Navigation instruments, autopilot, phone charging, cabin lights
Coastal passage
Moderate conditions		 24 hours 6 knots 6.1 kWh All electronics, refrigeration, plus battery top-up for next day
Ocean crossing
Steady trade winds		 7 days 7 knots 63.8 kWh Complete energy independence - no engine running required
Fast sailing
Strong winds		 12 hours 9 knots 4.6 kWh Maximum output maintained whilst minimising drag
How We Compare
See how this hydrogenerator stacks up against leading commercial units - at a fraction of the cost.
Feature Our Design Watt & Sea Duogen
Maximum Power Output 380W 300W 400W
Propeller Options ✓ Two sizes included Optional extra ✓ Multiple options
Operating Range 4-11 knots 5-10 knots 5-12 knots
Propeller Change Time 10 minutes 15 minutes 20 minutes
Material Options Glass-filled nylon composite Composite Bronze
Build Options ✓ DIY plans
✓ Kit form
✓ Made to order		 Factory made only Factory made only
Approximate Cost $1,050-2,350
(DIY: $1,050)
(Kit: $1,500)
(Made to order: $2,350)		 $4,400-5,650 $5,000-6,900
Expected Lifespan 10+ years
(glass-filled nylon composite)		 8-12 years 15-20 years

🎯 Key Advantages