Yes .. and no. Imho.
Nozzles etc will work fine.. if they are suitably matched to the desired
use.
For a *tug*, the desired size of the prop will be very large.
About double-triple in diameter, from that originally foreseen in the plans.
At THOSE sizes, I think it will work well, just like in normal tugs.
Underwates turbines, wind generators, towable regen, all have the same
effect.
The practical achievable results are weak, unless the surface area is large.
Third or fourth power of size, from memory.
The prop a tug needs, is very different from one desired for
recreational use.
An electric tug will likely work very well, technically.
However, you should plan for about 5x more battery capacitym fro 20
kWhr, with lion.
Somewhere in the 100 kWhr range.
If you have a tow, of 10x vessel mass, what you cannot have happen, is
lose control of it.
An extra 1-2 hours delay due to traffic, accidents, currents, official
government actions (police boats, etc) will sometimes happen.
Now you need to have use of the heavy thrust for an extended period of time.
You cannot stop, you cannot anchor (wont hold) and you cannot abandon
the tow (liability).
At a minimum, you should have full-tow capacity power, ie a diesel plant
able to deliver the required power, maybe 20-30 kW.
This is very much cheaper than the 100 kWhr lion batteries.
(A 30 kW commercial gensets can be had for 20k or so).
A tug is a commercial vessel.
It will need commercial permits, need to be inspected, and have plans
signed off by a naval architect.
Otherwise you will not be able to get insurance, or permits, that are
mandatory.
All sorts of regulations come into effect, and the net result is a great
increase in costs, re: permits.
Before building, the steel used must be submitted to the certifying
authority.
Welding will need to be inspected.
Its one (of many) requirements for commercial licensing.
You cannot home-build commercial vessels without the requirted
expertise, tools, and documented processes.
Some are onerous and not too expensive.
Some are quite expensive - like the naval architect.
At a minimum, you should plan on 50k for the permits alone.
You probably cannot use anything NOS, like from surplus center.
The naval architects and licensing authorities will likely not accept
these as confirming to the commercial regulations.
You will need commercial hatches, etc. These are expensive.
The genset will need to be meant for industrial use. Etc.
At 100k for batteries, 50 k for NA and permits and inspections and x-ray
of welds, 30k for continuous-duty genset, 50k (low end) for
commercial-rated wiring, tankage, hoses, plumbing etc. the project cost
may be getting too high ?
A commercial kort nozzle is about 30k, btw.
Now - you did mention a plan to commercialize these, and thus the
regulations are needed.
It totally changes the game.
If you build one for yourself, most of the above costs can be mitigated.
What you cannot do, is build it for yourself, and then sell it commercially.
Note liability attaches to the builder - that would be You in this case.
Unless the paperwork exists, you will likely not be able to get
insurance or sell the craft for commercial use.
At a minimum, consult a naval surveyor, with commercial vessel experience.
They will tell you more or less the same thing, at 3k$ / day.
Hope this is useful.
On 31/05/2014 01:39, dhennis@centurytel.net [electricboats] wrote:
>
> I also wondered if anybody reading these threads had any experience
> with a Kort nozzle on their EB (electric boat)? In my research, it
> would seem, that the addition of a Kort nozzle will increase
> efficiency in bollard pulls, as much as 30%. I suspect this will have
> a ripple effect to the battery life per charge, and the required
> throttle setting to achieve a desired setting.
>
>
> So what does anybody, (including Eric) think? Can I expect a 30% or
> less increase in the figures for power and duration?
>
>
> Thanks for all the help in advance.
>
>
> Aero_Dan
>
--
-hanermo (cnc designs)
