FWIW, as I have studied the subject for the last 8 years, almost full time .. re building yachts, on a budget and not ..
Forget the brand of the motors, immaterial.
Likewise with batteries. Lots of choices, whichever you buy, the money is gone and wont come back.
Li battery technology advances about 20% year/over year in electric vehicle sizes, which this is.
In both density/mass and density/$ terms.
Inverter efficiencies go to about 95-98%.
However, solar charger costs drop about 20-25% year/year in larger sizes.
This is likely to lead to cheap chargers within 3-5 years.
Pick whatever you are most comfortable with from a systems engineering viewpoint.
You cannot build or refit a modern, comfortable, hull for 100 k$ if you buy marine components, need work done professionally, or need to use classed equipment or extensive electronics.
Even assuming a free hull.
The situation changes if:
the fitout is allowed to be somewhat camping-level,
you have engineering and materials processing equipment and work available free,
(Industrial lathes, mills, benders, welders, planers, tablesaws, grinders, measuring equipment, lifting equipment etc etc),
can buy materials at bulk (multi ton worldwide) prices,
are comfortable integrating complex systems and can source components worldwide,
need minimal electronics like a typical sailboat or workboat.
Any of the 5 above can comfortably cost more than the 100k$ in tools or material alone.
Some points and examples;
2 x 8-10 kW motors, driveline, propellers, glands, thrust bearings etc etc will cost about 6-8000, plus installation. Each. And up from there, upto about triple for a yachty engineered solution.
Options:
I would get some truck axels, turn the ends, and second hand props and industrial components for the driveline. Total cost about 1500€ for 2. Assumes I can find 2 used props (easy, right size in kW).
Cons:
Needs metalworking tools, experience, scrounging, time.
Solar cells for 6 kW can be bought for about 2$/watt. Thats 12.000$.
Add 2 MPPT chargers 3000$ , cables 1000$, large fuses and contactors, etc, 2000$.
Add 6-20.000 $ for battery as desired.
For a 10k$ battery, thats 28.000 + minimum 2000 in bits (material only) before the solar cells are installed.
Installing high amp stuff is something that needs tools and know-how.
Both can be aquired, but it all takes time and money.
Minimum cost to fitout a living space in a boat, for 4, about 4-50.000$ (in the US or EU). Very low end.
Assumes home appliance style hw, well chosen and mounted, at trade wholesale costs.
Tanks, plumbing, valves, through hulls, waste tanks, pumps, paint. Todays prices when absolutely everything is planned in advance, bought at bulk prices (500 box of everything, nothing "marine" etc.).
The above does not include portlights, hatches, doors, locks, ventilation equipment, insulation, heating, electronics.
Note that ground tackle can easily cost 3-5000$ (anchor, chain, winch, work).
Basic furnishings are very cheap if bought Ikea style.
Note that there are lots of requirements you must comply with.
EU small craft directive (you can sign it yourself, but you gotta do it), and holding tanks are mandatory.
Otherwise, your boat is subject to surprise impounding if cruising in most of the world, these days.
These are just some points to take into account.
You can cut some corners (no interior, paint, use hull as-is, fittings for one (you may get lonely), etc.
I myself would buy all the bits, and sail to the nearest country with cheap labour (anywhere in the world works for me).
But I own and or can build all tools to do any of above projects, and would plan to have them with me.
As such, a large part of payload for me would be tools.
I am also used to integrating large projects in new cultures, with unusual languages and cultures. Ymmv.
It´s not hard. It´s not easy.
And you gotta know when you need the 500$ industrial tool and when a 39$ chicom knock-off will work.
Or spend an extra 3000 work hours at it.
A yacht in the 45 ft range takes about 12.000 hour to build.
Assume free hull (thats 1/3). Assume major equipment is mounted (hatches, portlights, tanks). Still leaves 20-30% or 2-3000 hours.
Double that if working alone, no experience, or not the right tools.
The Q you gotta ask is
- who does the work
- where
- with what equipment
- at what cost
Where you can save the most money, is buying the right stuff in advance.
This means being the primary contractor.
So, show me your detailed list of every bolt, but, washer, gland, paint, bit, switch, cable etc. that goes onboard.
Galvanic isolation where needed !
What grade of stainless ? Are You sure ?
What grade of cable (hint: cabling will cost 3-8000$ in material and work).
A typical yacht does 600+ hours (and lots more) in cabling work.
And where you will buy it.
Unless you do so, your costs go up about 10x for retail over the counter, in bits and pieces.
The price difference for the best (industrial stuff, large, bought well) is 33 times cheaper for given performance than for yachty marine stuff.
Thats right, cheaper. And 10x more reliable.
But you cant buy it at the nearest "x", and you cant buy small.
Shipping is cheap.
Just a list of things to take into account.
Hey folks,
I have posted occasionally but follow the discussions on the list with great interest in advancing battery and solar technology.
I am still looking to build my live-aboard cruiser in the 40-60 feet size range.
I know most of you guys are sailors, but the knowledge of solar and battery tech would be applicable.. so I am looking for recommendation on recreating this German solar boat on a budget. This is pretty much exactly what I want, a solar powered catamaran.. no sails, no regen, etc.
Please check this out
http://www.solarwaterworld.de/index.php?id=69&L=3
http://www.solarwaterworld.de/fileadmin/pdfs/SunCat-46-prospect-english.pdf
My current idea is to take a used aluminum or Fiberglass passenger ferry preferably with a blown motor(s) and strip out the engines and seats and convert it to a live aboard with electric power and a large solar array over the entire top of the boat.
This will be augmented with a larger genset when needed for emergency reasons.. but ideally the genset will rarely need to be started.
I would want battery storage to allow for 24 hours of cruising at around 5 knots.
The boat will be designed to hop between the islands in the Caribbean, and this should allow plenty of time for the array to top up the batteries if consumption has exceeded the solar array capacity.
So.. if this were *your* project, what would you recommend for brand and sizing the electric motors, what brand and type of batteries would you buy (Lithium or equivalent technology), what controller and what and where would you get the solar panels from?
How tall would you make the vessel, what should I consider in terms of weight and positioning of the array?
Is there a practical way to make an array of this size "directional", i.e. follow the sun.
The more detailed you can be the better. If you know of someone else that has put together a non-sailed cruiser in this sort of size range and has a blog, that would be awesome too.
I want to keep the cost of the whole project considerably under $100K. :-)
Many thanks!
Kind regards,
Bill
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