Outboard motor

elect70, Dec 12, 11:05am
fitting an electric OB to inflatable how far below the bottom of the hull should the prop be set at ?

snork28, Dec 12, 11:34am

wind.turbine, Dec 12, 11:42am
the anti cav plate should sit inline with the keel,
really crucial for speed and economy on a 40hp plus but for a electric on a dingie is not so much a concern

s_nz, Dec 12, 3:33pm
As above if it has a anti-cavitation plate, use that as the reference.

If not, generally you want the entire propeller in the relatively clean flowing water under the hull (and if if the outboard is powerful enough to plane, this will mean the prop won't break the surface).

Any deeper adds to drag and draft without much gain elsewhere.

mrcat1, Dec 12, 7:21pm
Should pay to note, that is the lowest you want to go with the anti cav plate, you can go higher though.

wind.turbine, Dec 12, 9:15pm
not necessarily, you may want to go deeper if its not speed you are after, like a boat that is used for heavy loading applications, cav plate running along surface of water is the standard, then you start going higher if you are chasing speed but then this can cause ventilation in hard turns but not normally an issue if you are chasing speed

s_nz, Dec 12, 10:48pm
Was going to say that the likes of thundercats run the waterline at about the elevation of the propshaft, but I thought it might not be so relevant for a dingy application.

elect70, Oct 10, 1:59pm
This OB is sold as a trolling motor 65 lb thrust & doesnt have a anti cavitation plate so i presume use the top of the prop for depth reference This is not for speed just to tow mono line out to 2 kms + as kon tiki would only go 1 km & now the clam dredge rapes to sea bed up to 1km offshore & fish all gone into deeper water

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