THE ELECTRIC BOAT
The boat (Hammer P) owned by Kerri and Helen Jamieson, is a 1966 -35 ft. OWENS flagship. She is double plank mahogany on oak frames, Teak decks and fiberglass cabin shell. Equipment when we got her included mismatched and somewhat tired Ford/8 engines, Borg-Warner Velvet Drive transmissions all fresh water-cooled. Also outfitted with a 6.5 KW Kohler Gen-Set.
By mid 2006, I had decided that re-powering was essential. Having toyed with the electric idea for a year or so, I finally decided- "Just Do it" and began the search for a supplier for all the components. After considerable browsing catalogs and online information, this is what I chose for our application: (This is basic electric stuff)

2- Advanced DC Motors-L91-4003-13hp-72Volt
2 -Altrax 7245 motor controllers
2 -Merritt Inline Joystick control
2 -Albright Main Contactors
2 -Albright Reversing Contactors
3 -400 amp Ferraz/S'mut Safety Fuses
1-Link 10 E Meter
2-0nboard Charger 48-108 volt
3-Deltec Amp meter shunts
2-Westberg Ammeters
180 Lin. feet 2/0 Welding cable
90 Cable Lugs
24 -L 16H Trojan Batteries That is pretty much the electrics of the system, plus misc. hook up wire, etc.

The Mechanics portion needs some thought: Motor to shaft reduction, belt tensioner and battery placement. I had to lengthen the propeller shaft to accommodate the larger pulley for a reduction ratio. I chose a 4:1 reduction because the motors need to turn fast enough to run cool and I need 1000rpm at the shaft to match our previous cruising speed. The rest of the mounting hardware is like a big erector set. All bolted parts were pre-drilled except for bolting to the original engine bunks. These were bolted in place after the shaft augmentation. Motor mounts are adjustable for belt tension and tracking.

There are two flange bearings each side, and opposed for thrust bearings. This all makes a fairly compact package and then we had to decide on battery placement. In our case, we designed a 72 Volt system. Battery placement was somewhat a balancing act. Original components, (fuel) were stored behind the drive train and of course, motors amid ship. Fuel weight (160 gallons) this was about 1300 Ibs. Motors and transmissions about 1500 Ibs. New battery pack weight: about 3000 Ibs. To best balance the boat, I put 8 batteries forward and four behind each motor. With motors, batteries and electrical equipment we have an approximate weight gain of 1000 Ibs.

Finally, in 2010, I installed 45 watts of solar panels to keep the house batteries charged. With this we can count on continued use of lights and intermittent use of the 2000- watt inverter for the Microwave and cook-top.

The Hammer P has a range of 40 to 60 nm (depending on weather and speed).

 
If you would like to discuss this information further, please give us a call at: 253-884-3691- or email Kerri at hammerp@centurytel.net