Need cooling advice

[Charles Newman]

Have been running the recently converted Dumas DV and the ESC seems to be getting too hot evidenced by limiting the speed after running fast for a while.

Here is my current cooling pickup. I can see water coming out of the cooling outlet when moving, so it is not blocked.

Any advice appreciated. IMG_1621.jpg
IMG_1622.jpg

[fweasel]

I assume this is a standard, surface piercing prop? It looks to be. You're running it fully submerged, which puts significantly more load the motor, which means more amps, and more heat. Another source of heat in an ESC, although to a lesser degree than the prop issue, is a lot partial throttle running time. ESC's prefer to be run at wide open throttle in terms of efficiency.

[Charles Newman]

The prop is a "CNC Prop 44mm 3 BLD - 3/16" bore"

Thanks

[Dr. Jet]

I find I have a better water flow when the pickup is near the tip of the prop where it sheds the most amount of water to create the typical rooster tail. If you watch a boat going away from you, you can often see that the rooster tail looks more like a sheet instead of a cone. I try to get it in line with that sheet.

[Charles Newman]

I find I have a better water flow when the pickup is near the tip of the prop where it sheds the most water to create the typical rooster tail. If you watch a boat going away from you, you can often see that the rooster tail looks more like a sheet instead of a cone. I try to get it in line with that sheet.

Thanks I'll give that at try today!

[fweasel]

The prop is a "CNC Prop 44mm 3 BLD - 3/16" bore"

Thanks

That prop was designed to be run half in, half out of the water, with a driveline that exits the transom above the keel. You've got it fully submerged. My point is, it's possible all the cooling tweaks in the world may not be enough to cool things down from that much load.

[Dr. Jet]

I didn't see that he was running it as a submerged drive. If that is the case, then fweasel is absolutely right; prop it down until you find something that doesn't load up the motor/ESC so much.

[Charles Newman]

Thanks, what prop do you recommend.

Setup:

Motor: Leopard 4074 Motor | Offshore Electrics 1400kv
ESC: OSE Raider 6s 150amp
Batteries are 6s

[Dr. Jet]

The previous prop worked OK and didn't start an immediate fire, so I'd start with 2 blades and maybe 40mm diameter. If it still gets hot, keep going smaller; if it doesn't even get warm, go to 42mm.

I'm assuming the prop you had was 1.4 pitch ratio, and I would not go any higher than that for submerged drive. I'd even look for 1.2 pitch props for submerged applications.

[Charles Newman]

Thanks for the suggestions. It is a bit costly spend $25 + $8 shipping to test each propellor. I have some old two blade props from the gas engine I could try.

[jingalls007]

Thanks for the suggestions. It is a bit costly spend $25 + $8 shipping to test each propellor. I have some old two blade props from the gas engine I could try.

Snag a few glass props from OSE. They're inexpensive, you can test which ones work, then you can buy a metal prop in the sizes that work best: https://www.offshoreelectrics.com/pr...d=ose-2bld-316