Grapeview Point Boat Works' 21 ft. 3 in. Electric Launch
Specifications
| Length |
21 ft. 3 in. |
| Beam |
7 ft. |
| Draft |
21 in. |
| Displacement |
3200 lbs. |
| Capacity |
10 adults |
| Power |
6 hp Electric Inboard with 15" prop, 48v 21 KWH Battery Bank |
| Battery Charger |
Fully Automatic, onboard, 115v 15A input |
| Typical recharge time |
Overnight |
We are currently building a 21'3" x 7' x 21" launch based on a Nelson Zimmer design.
Grapeview Point Boat Works Electric Launch based on a design by Nelson Zimmer
Instead of the carvel construction shown on the plans, we are building a lapstrake hull with okoume plywood planking on bent oak frames. The floors are also oak, with sapelle backbone and transom.
When completed the launch will be totally enclosed with a rigid canopy and windows all around, most of which will be hinged to swing up under the canopy.
We'll be installing a 48v 6HP (12HP peak) PMAC electric motor powered by 16 6v AGM golfcart batteries. With a syncronous belt drive we will have a 2:8 to 1 reduction to turn the 15" x 12" prop at about 850 rpm maximum. This will give us about a 6 kts max speed with a 5 kt cruising speed. Cruising range at 80% depth of discharge should be around 40 miles, considerably more at slightly slower speeds.
The motor, reduction gearing and batteries will be entirely under the cockpit sole, leaving an open cockpit area over 6 feet wide and 14 feet long.
This launch will be perfectly suited for nearly silent cruising in semi-protected waters with up to 10 occupants.

Backbone and transom frame of the launch. Propeller shaft and stuffing box being fitted.

The first few strakes are hung on the bent oak frames

The launch rudder with mockup of the proposed propeller. Rudder heel bearing is supported by 3/8" bronze plate.

The interior of the launch takes shape. Temporary wooden knees hold the coaming pattern plumb.

The interior of the launch

The center sections of the plywood cockpit sole are removable for access to batteries and motor.

The jog in the hatch outline allows for a future enclosed head when the rigid canopy is installed.

The bin to port opens to reveal the depth sounder and watt hour meter. A drawer is to starboard, below is a shallow locker for the DC distribution panel.

The oak planksheer is being fitted. Wicker furniture was often used on the early electric launches. It allows configuring the seating to suit the number of guests, and allows everyone to face the view.

There is plenty of room for seating and tables for eight, plus a helmsman who typically sat on a wicker stool.

The aft deck is strip planked with sapele.

The completed aft deck.

The forward section of the coaming is bent over a trap, then fitted to the boat when cooled.

The entire length of the stem and keel is protected by 1/8" bronze plate cut to shape. A mock-up of the port and starboard steps is being tested.

The 5/8" coaming was bent in cold, and carefully fitted to be plumb along its length.

The steering is via cable and pulley. The cables will exit the bulkhead and run aft just below the coaming. The throttle control is to starboard.

The construction is complete and is currently being prepped for paint.
Have questions or comments? Send us an
email at boat_works @yahoo.com.
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