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I sat down today with my box of receipts to get a rough total of the materials costs for my AROHA project so far. I am sure I have missed some receipts/invoices, but the totals below should be pretty accurate. I have not yet purchased the listed items for which there are not costs shown. I believe I have on hand, and these costs include, almost all of the materials needed to finish the project, except for the un-purchased items listed below and except for more epoxy, paint and varnish. The pilot house roof is the only major structure I have not yet built. I am using electric propulsion, which is not inexpensive but avoids the cost of a diesel engine, muffler, fuel tanks, fuel lines, etc.
Costs:
Hardware, including drive shaft, bearings seal; and misc. consumables like abrasives and needed project-specific tools like router and drill bits and boring bar: $4,350
Epoxy (West), fiberglass cloth, paint, varnish, paint brushes and roller covers: 5,944
Mahogany lumber: 1,071
Douglas fir (about 600 board feet) 2,892
Hewes & Company CNC-cut plywood/AvanTech kit (current price is higher) 4,765
Plans 349
Meranti Plywood (Homestead Hardwoods, Vickery, Ohio) 3,095
Propulsion (Electric Motor, Batteries, Misc. electrical parts) 18,007
Used steering wheel 200
Pilot house windows and coach house portholes glassBattery charger
Propeller
Rudder shoe
Trailer
Half oval rub rail, cleats and other deck hardware
Total $40,628
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Hi John – It’s good of you to share this. Quite eye opening. Boat’s like these are indeed a labor of love; I like to think building one is cheaper than psychotherapy!
I suspect a build like yours, coming out of Brooklin Boat Yard would run in the $150,000 range.
Looking forward to seeing your completed boat. Thanks
Doug Hermann
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My electric propulsion choices:
After talking or emailing with all of the electrical marine propulsion suppliers I could find on the web who would respond, and with a little bit of information about the electrical propulsion system AROHA/WHIO designer Peter Sewell has now installed on WHIO, I have purchased:
1. Motor, including display, controls, etc.:
Electric Yacht QuietTorque™ 20.0 Electric Motor, described here:
https://electricyacht.com/product/quiettorque-20-electric-motor/
This system is actually two 10 kilowatt motors that are both coupled to the same drive shaft. This configuration makes it possible for this to be a 48 volt system. For practical reasons, larger motors require higher voltage.
2. Batteries:
I am installing eight Lithium Ion batteries in two banks of four series-connected 12 v batteries:
SOK Marine Grade 12V 206Ah LiFePO4 Battery, Sealed Plastic Box
They weigh 48 pounds each and are described here:
3. Other information:
I can squeeze four of the SOK Marine batteries into each of the side benches depicted in the AROHA drawings, so this propulsion system will occupy the same spaces as the diesel motor and fuel tanks specified for AROHA. I judged battery systems other than lithium to be too large and heavy to be practical.
Watch Youtube videos by Will Prowse for information about LiFePO4 batteries and related matters.
Higher than displacement hull speeds (around 7 knots) are possible because the AROHA hull shape is a semi-planing hull, rather than just a displacement hull.
I chose the Electric Yacht system based on an industry recommendation of the company, my own interactions with the company and my guesstimate that this system will do what I want.
I will report ranges possible at various speeds when I have some experience on the water. I plan to use the boat for day outings on a large mountain lake, so I expect to be satisfied with relatively small range/running time numbers.
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