Calculator…

…is being updated.

Meanwhile, here are some measurements…

EP Carry provides the power and the battery provides the run-time and range.

EP Carry-supplied Batteries include a buoyant soft case and power cord:

6-lb Battery from EP Carry: 24V, 11.2 Ah, $460, @ full-throttle provides 1 hour or 2-3 days of ship-to-shore service

14-lb Battery from EP Carry: 24V, 30 Ah, $560, battery monitor, @ full-throttle provides 3 hrs.

EP Carry also supports 12V, 24V and 36V user-supplied batteries. The most popular options:

24V, 50 Ah from Li Time®:  Typical cost $315, weight 21-lb, battery monitor, @ full throttle, provides 5 hrs.

12V, 100 Ah from Redodo®:  Typical cost $256, weight 23-lb, battery monitor, @ full throttle, provides 5 hrs. For full-power performance, 12V batteries require our 12V boost kit.

full-throttle speeds and ranges.

BoatLoaded Boat Weight
lb		Full Throttle Speed
knots, (mph).		1-hr battery range
nautical miles (miles)		3-hr battery range
nautical miles (miles)		5-hr battery range
nautical miles (miles)
Typical 8-ft inflatable or RIB– 450 lb.3.2
(3.7)		3.2
(3.7)		9.6
(11)		16
(19)
True Kit Navigator 2.5 (8-ft) inflatable– 450 lb3.5
(4.0)		3.5
(4.0)		11
(12 )		17
(20)
Typical 9-ft inflatable or RIB– 450 lb.3.4
(3.9)		3.4
(3.9)		10
(12 )		17
(20)
Typical 10-ft inflatable or RIB– 450 lb.3.5
(4.0)		3.5
(4.0)		10.5
(12 )		17
(20)
Typical 11-ft inflatable or Rib– 450 lb.3.6
(4.1)		3.6
(4.1 )		11
(12 )		18
(21)
11 ft True Kit Tactician Inflatable dinghy – 450 lb.3.8
(4.4)		3.8
(4.4)		11
(13 )		19
(22)
7.5 ft Eastport Pram by CLC– 300 lb.3.6
(4.1)		3.6
(4.1 )		11
(12 )		18
(21)
9 ft Minto rowing sail/row– 340 lb.4.0
(4.6)		4.0
(4.6)		12
(14 )		20
(23)
10 ft Tenderly by CLC– 450 lb.4.0
(4.6)		4.0
(4.6)		12
(14 )		20
(23)
10 ft Navigator– 250 lb.4.1
(4.7)		4.1
(4.7)		12
(14 )		21
(24)
10 ft Walker Bay rowboat– 450 lb.3.7
(4.3)		3.7
(4.3)		11
(13 )		19
(22)
12 ft Captains Gig by GHB– 520 lb.3.9
(4.5)		3.9
(4.5)		12
(14 )		20
(23)
12 ft cedar strip rowboat– 450 lb.4.2
(4.8)		4.2
(4.8)		13
(14)		21
(24)
12 ft Scamp– 1,100 lb.3.5
(4.0)		3.5
(4.0 )		11
(12 )		18
(20 )
Old Salt 15-700 lb.3.7
(4.3)		3.7
(4.3 )		11
(13 )		19
(22 )
Core Sound 17 Mk3-1,300 lb3.0
(3.4)		3.0
(3.4 )		9
(10 )		15
(17 )
19.5 ft Long Steps– 1,100 lb.4.2
(4.8)		4.2
(4.8 )		13
(14 )		21
(24 )
17 ft Salish Voyager by GHB -900 lb.4.1
(4.7)		4.1
(4.7 )		12
(14 )		21
(24 )
14 ft C-Lark-900 lb.4.0
(4.6)		4
(4.6 )		12
(14 )		20
(23 )
14 ft Native Watercraft fishing kayak-350 lb4.6
(5.3)		4.6
(5.3 )		14
(16 )		23
(27 )
12.5 ft Jackson fishing kayak– 260 lb.4.2
(4.8)		4.2
(4.8 )		13
(14 )		21
(24 )
21 ft proa-600 lb3.7
(4.3)		3.7
(4.3 )		11
(13 )		 19
(22 )

Half power: Half-throttle range is roughly 1.5 x full-throttle range, and half-throttle speed is roughly 75% of full-power speed. Here’s an example:

The 14′ C-Lark with the large battery has a full throttle range of 20 nm at 4 knots. At half-throttle, range is 1.5 x 20 nm = 30 nm, and speed is 0.75 x 4 knots = 3 knots.

Your speed also depends on boat loading, winds, waves, currents and boat trim.

The effect of currents is easy to account for; add or subtract the current speed from your boat speed.

Accounting for winds and waves is more complex, but it is useful to know that a head wind will slow the boat with an electric outboard less than with a gas outboard (an electric motor produces constant torque under increasing loads whereas a combustion engine looses torque). Conversely, a tail wind will add a little speed, but like a sailboat going down-wind, the additional boat speed produced by a following wind reduces the relative wind, so the downwind effect on speed helps only slightly, unless it’s really blowing.

You are in charge of your boat’s efficiency. Here’s how: Keeping your boat level fore and aft will maximize its efficiency going through the water. Dragging swirling water behind a deeply immersed transom makes for an inefficient boat so shift weight forward to reduce transom immersion and you’ll be surprised at the pickup in speed.

See testimonials.