Semi Permanent Electric Drive

I have been thinking of fitting my 44lb trust electric motor to the hull as a semi permanent fixture as I always have it fitted when cruising the local river Tees.
The plan is to make a hole in the bottom of the hull and pass the motor stem through a sealed gland.  The motor will lift up and down slightly to get the right depth preventing cavitation and also be able to be swivelled for trimming and more control in tight manoeuvres.
The controls will be plugged in and mounted "somewhere".
If the motor is removed the hole will be plugged.
Any comments and, advice would be appreciated.

 

Hi Tony,

I've been wondering if anyone else would jump in with a view on this idea, but they haven't, so here are my thoughts, for what they are worth...

PRO:
I like the idea of having a prop directly in front of the  rudder. It has the potential of making the steering via the tiller when under power so much more responsive.

I like the neat appearance of an engine mounted within a well in the aft deck of a boat (I almost bought a Swift 18, rather than a SeaHawk, because of the way it mounted the outboard within the cockpit.)

CON:
I believe that making large holes in the hull any boat will drop its value as it takes time, money and expertise for the next owner to reinstate things. They are unlikely to want your specialised change. (Sensors for depth sounders or a sink drain, would be my limit!)

Neither do I do I like the idea of cutting much more than bolt holes in the superstructure, come to that. Repairing and smoothing large curved areas is much trickier than filling holes where screws once were.


Swinging the prop makes little sense if it's already positioned in front of the rudder. I wouldn't go to the trouble of making it movable. Instead, be prepared to write off the motor's potential resale vale. Cut off the majority of the shaft. Fit the shortened shaft with a bracket and bolt that to the hull. Then you only need to pass the cable through the hull, a relatively small set of holes that shouldn't put too many people off removing the motor and re-instating things. Similarly, mount the engine controls in a surface mounted box, rather than making large holes for motor controls direct in the cockpit.

However, I would worry that my plan would place the motor at risk when using a slipway. (Perhaps this is why you want to cut a bigger hole and allow the engine to be removed?)

Overall, I find the Minn Kota engine so light and easy to manage that I see no problem with lifting it on and off the transom as required. When I'm on the three Rivers Race it gets stowed it on one of the bunks. It's even possible to sleep with it there!

So I conclude, why bother with the project at all?

I'm with Greg on this one!  Why not just attach the electric motor to a bracket at the stern? Then you can lift it out of the water when sailing.   That way you can overcome another 'con' which is that the prop permanently under the hull will create significant drag.  One of the virtues of Seahawks is that the hull is nicely 'slippery' compared to other trailer sailers, and I fear your arrangement would not improve sailing qualities.  

BTW - I'm a fan of electric outboards, especially when coupled to a big battery and a good solar panel.   Last summer I saw a Folkboat with such an arrangement - the owner said he could get 5 hours running at half power.  Very impressive!  I use a Minnekota for trout fishing - love it.  

Thanks for the comments.  I have a 44lb thrust which I use at present with it's standard bracket.  I use this on the transom as per standard set up.  I find that it does tangle with the main sheet when lifted out of the water, so I tend to leave it down.  This has the advantage of being able to give a quick burst of power if we look like getting into trouble on the river.  We have to contend with overhanging trees and fickle winds on the Tees.  I don't think it creates much drag, unlike a petrol outboard with a gearbox to drive. Just yesterday we managed a credible 4.9 MPH on a reach in a force 4.  This must be getting towards hull speed, has anybody worked this out?
The batter is an 85 amp cyclic type located in the centre cabin locker to keep the weight forward and wired to a 50amp connector in the starboard cockpit locker so it is easy to plug the motor in.  Without running the battery to completely flat, I reckon on about 4 hours running time at various speeds and conditions. saving up for another battery and considering solar panels but these are expensive for the right quality.
Charlotte III is not all that smooth yet!.  There is a build up of anti-fouling that I intend to remove as she is stored off the water.  But even with this rough bottom she goes really well and I am well impressed with Seahawks.

I must admit I am still thinking about doing this modification!!!!!. Regarding the hole in the hull, this would only be 28mm dia. to take the slim shaft the motor is attached to. The motor would be removable and/or lift-able if a slipway looked dodgy.