Csail
N/A
What does a 18lbs thrust electric compare to in the petrol outbd world?
Electric outboards
- Thread starter Csail
- Start date
geoffatstanpit
Well-Known Member
Motor thrust
My 5hp Mercury (4 stroke) gives 40Kg thrust (about 88Lb) at full chat. That gives me just over 5 knots on a Parker 21.
My 5hp Mercury (4 stroke) gives 40Kg thrust (about 88Lb) at full chat. That gives me just over 5 knots on a Parker 21.
Silent Lady
Well-Known Member
Thrust =
THRUST(lbs) = ( HP * 325 ) / Velocity (knots)
So if a Honda 2HP powers a boat at 4 knots the engine will be producing
2 * 325 / 4 = 162 lbs of thrust
I have tried an electric motor on the river . Against a 2 knot current it was very slow . Think you need a good battery . On a flat lake no current it would probably be fine . Think you also have to take the wind into consideration as well . If they were that good we would all be using them .
THRUST(lbs) = ( HP * 325 ) / Velocity (knots)
So if a Honda 2HP powers a boat at 4 knots the engine will be producing
2 * 325 / 4 = 162 lbs of thrust
I have tried an electric motor on the river . Against a 2 knot current it was very slow . Think you need a good battery . On a flat lake no current it would probably be fine . Think you also have to take the wind into consideration as well . If they were that good we would all be using them .
Jenaline IV
Well-Known Member
I have a 54lb thrust Rhino which I use on an 11ft dinghy. On the canals and lakes it is fine and in fact the fishermen and walkers seem to appreciate the lack of noice and pollution it brings. (as well as the underwater survey from my fishfinder!) It saves me £34 a year on my canal boat license.
On the sea it is not practicable against the tide for obvious reasons. My dinghy is also rigged for sail so I usually use it in emergencies and for close quarters only. I have used it soley under power in Poole but it required planning to ensure that the tide wasn't going to catch me out. When used with the tide it is very effective in getting from A to B.
I use 2 x 70 AHC leisure AGM batteries which can be switched between either bank or dual. I use one for getting me to where I want to go, one to get back and then both in emergencies or if I get low on juice. The AGM lets me Deep discharge to 8V without problems and on speed 3 or 4 (out of 5) I get about 4-6 hours pottering on the water. If I used speed 5 all the time I get about 2 hours.
I dont have accurate speed through the water yet as I didn't have my gps at the time but going on rough dist x time calcs speed 4 is about 5kph
On the sea it is not practicable against the tide for obvious reasons. My dinghy is also rigged for sail so I usually use it in emergencies and for close quarters only. I have used it soley under power in Poole but it required planning to ensure that the tide wasn't going to catch me out. When used with the tide it is very effective in getting from A to B.
I use 2 x 70 AHC leisure AGM batteries which can be switched between either bank or dual. I use one for getting me to where I want to go, one to get back and then both in emergencies or if I get low on juice. The AGM lets me Deep discharge to 8V without problems and on speed 3 or 4 (out of 5) I get about 4-6 hours pottering on the water. If I used speed 5 all the time I get about 2 hours.
I dont have accurate speed through the water yet as I didn't have my gps at the time but going on rough dist x time calcs speed 4 is about 5kph
Ubergeekian
Well-Known Member
Check what the manufacturers say ... and half it, he said, cynically.
lookwide
New Member
I use an ageing 32Lbs electric out board (purchased on E bay) with a 85ah leisure battery on a 9' Avon redcrest and regularly travel over 1 mile to my mooring in Portsmouth harbour, Occasionally with the wind blowing with the tide i have to row to assist but otherwise rairly have any problems.
Best purchase in ages!!!!
Best purchase in ages!!!!
rich
Well-Known Member
Have a look at these, powerful,& fairly cheap.
http://www.billhigham.co.uk/flover.php
I have this one on my daughters mirror offshore
it pushers the boat well, we keep the battery charged by solar panel, Flover55TGS Outboard
http://www.billhigham.co.uk/flover.php
I have this one on my daughters mirror offshore
it pushers the boat well, we keep the battery charged by solar panel, Flover55TGS Outboard
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VicS
Well-Known Member
I use a small petrol outboard, no idea how much thrust it produces but it is only 1½ hp. I suppose being 36 years old it could be described as ageing.
It uses a little more ½ litre of petrol for the 1 mile round trip to the mooring and back but if necessary it can be refuelled in a couple of minutes or so from a can of petrol .... rather quicker than recharging a battery .... and can be refuelled several times over from a 5 litre can.
I don't have to hump a whacking great battery about, let alone two of them!
But you cannot use it to push the boat the length of the Solent and back in a weekend. I can push a similar sized boat that distance and more if desired with a 5 or 6 hp petrol outboard at hull speed with ease even when the sun isn't shining.
An electric outboard may be just the bees knees if you want to travel relatively slowly for short distances in relatively sheltered locations with no strong foul tides in complete silence and don't mind humping a whacking great battery around.
Otherwise no competition with a small petrol engine!
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lookwide
New Member
Petrol V Electric
Vic, I agree the electric outboard will not push a reasonable sized boat along and they do have other problems, but they do have many advantages, I would suggest my battery and outboard lifted as separate items weigh less than the average 5 hp Petrol, I use to use the boom and topping lift to get mine onboard!
Refilling an empty (hot!) petrol outboard in a bouncing dinghy is not a good idea,However when the battery runs low the motor will continue to run albeit slower and should get you to safety.
I have the ability to recharge the battery from the charging cuircuits on the boat when cruising either from the engine or the solar panels.
Don't get me wrong,I still have my petrol outboard and it has its place however for general use I prefer the silence of electric power.
Vic, I agree the electric outboard will not push a reasonable sized boat along and they do have other problems, but they do have many advantages, I would suggest my battery and outboard lifted as separate items weigh less than the average 5 hp Petrol, I use to use the boom and topping lift to get mine onboard!
Refilling an empty (hot!) petrol outboard in a bouncing dinghy is not a good idea,However when the battery runs low the motor will continue to run albeit slower and should get you to safety.
I have the ability to recharge the battery from the charging cuircuits on the boat when cruising either from the engine or the solar panels.
Don't get me wrong,I still have my petrol outboard and it has its place however for general use I prefer the silence of electric power.
VicS
Well-Known Member
Nothing to beat the music of a British Seagull though.
Only 13kg. Less than my 60 Ah leisure battery by 5 Kg but I must admit rather more difficult to handle.
When the Seagull wears out perhaps I'll try an electric model .. well I wont 'cos it'll outlast me many times over.
