Would a wide inlet with screen filter for low flow work better? Where is the spot that delivers lowest potential for blocking and highest potential for clearing blocks easily? In the transom maybe where a wider screen could be placed over the inlet. Possibly having outlet next to inlet would be self clearing and rely on water mixing to keep cool enough water coming in? Would hull side be better where velocity of water might tend to clear blockages and or minimise them - potentially having smaller outlet would create higher velocity water to push away debris and wider inlet to get better mixing.
On 11 Jun 2025, at 8:29 pm, Larry Brown via groups.io <elcapitanbrown=gmail.com@groups.io> wrote:I wonder if there's a high temp solution for a clear cylinder with heat exchanging stainless components inside where the fresh water runs through the inner steel conduit and the saltwater runs around it but inside the clear sleeve. You could see the state of the exchanger like you can see the state of a raw water intake filter. Heat exchangers are normally all closed off and everyone avoids dismantling them for inspection. The other problem with water cooling is the intake aperture. Because it's as small as it is, with as much suction as it has, it's easy to suck plastic bags or floating grass into it to clog. I wonder if you had a plate made that was say 12" x 12" with a lot of smaller holes that would spread the suction out, it might not clog so easily. Another option might be to have an external hose above the water line connected to a stainless cylinder with holes around it like the strainer inside a raw water intake filter. This could be held at the back of the boat out of the water from a davit or similar with an arm that drops it down under the water's surface when you need the motor. It would be way easier to see if it has something fouling it. It would be super easy to clear, and it would not leave a permanent hole in the bottom of the boat. Downside would be that the hose would get eaten up by the sun if it was left out. Maybe it could be made with a regular garden hose and when not in use it could coil into a cockpit locker. IDK if that size hose would give sufficient flow etc but it would be fun to play with and see how well it works. It would require a self priming pump which will probably have a shorter life cycle.Having designed electronic equipment for half a century, I have some experience in reliability. Powers needed for effective propulsion need water cooling. Losses in copper and iron are significant and removing this heat out of the motor area is difficult but made considerably easier with liquid cooling. Also lower operating temperatures means performance does not to be derated for hot weather. The controller, even with the very latest design will be dissipating closer to 1kw - think of that nice electric heater keeping you warm. It glows red hot . Electronic systems are most reliable around 25c and above 50c things start to get difficult to design in reliability.Liquid cooling is a highly mature field of engineering. Salt water heat exchangers work exceptionally well if regularly maintained. However it might prove more reliable to run a heat exchanger like used on diesel engines with a radiator to transfer heat to air . Maybe both?Best regardsLee Eldridge0427874796On 11 Jun 2025, at 10:24, Matt Foley <matt@sunlightconversions.com> wrote: Air cooled is possible at 10-15kw as long as it's designed for it. Can even push it to 20kw with a lot of air exchange. Also keep in mind, I wouldn't do an air cooled 20kw, if you planned on actually using the full 20kw for hours on end.Matt FoleySunlight ConversionsPerpetual Energy, LLC201-914-0466ABYC Certified MarineElectrical TechnicianOn Tuesday, June 10, 2025, 8:30 PM, Lee Eldridge <lee@vombatus.com.au> wrote:
have a look at freerchobby.seems dodgy name but people I see on youtube are using their motors etc. outspinnermotors are highertorque lower speedBest regardsLee Eldridge0427874796On 11 Jun 2025, at 04:41, cammcnally10@outlook.com via groups.io <cammcnally10=outlook.com@groups.io> wrote:Thanks Peter,I would prefer an air-cooled system but did not see any engines listed on Thunderstruck that also met all my other requirements. I am still trying to figure out what specifications of an engine to value above others. I will definitely reach out to them as they have only received good reviews from this group.-CM--Larry BrownS/V FelicityPlacida, FL~~~~~~~~~~~~~~~~~_/)~~~~~~~~~ ~ ~~ ~~ ~~_/) ~ ~ ~ ~~ _/) ~
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