Hello I've got a little 8 foot inflatable dingy for getting back and forth to our boat. I was wonder if a 8-10 pound thrust electric engine would be able to push the dingy we would be a bit less than 400 pounds with us and supplies plus engine and battery weight. The row is pretty long and can be into wind and current was thinking this might be a nice helper.... or is a 30 pounder in order? Thanks Don
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Don , the time has come to speak of many things.
Of drag and wind and waves and progress. If you really want to know the answer to your question, then you can set out with a length of line and a hand held scale. Tie off to your boat and let out a hundred feet or so of line on a moderately windy day. allow yourself to drift back until your tether is holding you in place and pull in ten feet of line and attach the handheld scale and read the load. That number will be the static load that must be applied to hold position. To make progress against that you must add power. My short answer is I don't think ten pounds thrust is enough. In a hard dink maybe but not an inflatable.
Of drag and wind and waves and progress. If you really want to know the answer to your question, then you can set out with a length of line and a hand held scale. Tie off to your boat and let out a hundred feet or so of line on a moderately windy day. allow yourself to drift back until your tether is holding you in place and pull in ten feet of line and attach the handheld scale and read the load. That number will be the static load that must be applied to hold position. To make progress against that you must add power. My short answer is I don't think ten pounds thrust is enough. In a hard dink maybe but not an inflatable.
11' Inflatable
On my 11' Inflatable, even my ~50 lb or so thrust MinnKota sometimes gets dicey - On a lake with no waves, but plenty of wind, to deal with. Of course, you can always add paddles if you don't have to go farther than your endurance. IMHO, a 2-3 HP outboard is better - but my electric was pretty cheap and works for my use. It is roughly a 1/2 horse motor, to put in in perspective. Lots of folks on our lakes use 35+ lb thrust electrics on dinghys to get out to moorings. OC
On my 11' Inflatable, even my ~50 lb or so thrust MinnKota sometimes gets dicey - On a lake with no waves, but plenty of wind, to deal with. Of course, you can always add paddles if you don't have to go farther than your endurance. IMHO, a 2-3 HP outboard is better - but my electric was pretty cheap and works for my use. It is roughly a 1/2 horse motor, to put in in perspective. Lots of folks on our lakes use 35+ lb thrust electrics on dinghys to get out to moorings. OC
Don't think so either
I don't think that is nearly enough motor. I would second the notion of a 2 or 3 hp outboard. It will be lighter than a decent size battery. Then if the wind picks up, you won't have to worry about it.
I don't think that is nearly enough motor. I would second the notion of a 2 or 3 hp outboard. It will be lighter than a decent size battery. Then if the wind picks up, you won't have to worry about it.
AQll things electric
Sadly we won't have a dingy dock to keep our boat at for several months most likely this season due to red tape. So At the moment the plan is to inflate and deflate each time we go out. Even when we have a dock security is probably going to be an issue. The electric would allow us to break it down and throw it in the trunk of our little car, which isn't really possible with a little outboard really as it would be laying on its side quite a bit and the car would smell of gas. It would also require even more planning than leaving the inflatable in the trunk all the time. Basicly I have the ability to pick this motor up for 20 bucks.... so no one thinks its a good idea? Not even as a helper to make rowing a bit easier? Don
Sadly we won't have a dingy dock to keep our boat at for several months most likely this season due to red tape. So At the moment the plan is to inflate and deflate each time we go out. Even when we have a dock security is probably going to be an issue. The electric would allow us to break it down and throw it in the trunk of our little car, which isn't really possible with a little outboard really as it would be laying on its side quite a bit and the car would smell of gas. It would also require even more planning than leaving the inflatable in the trunk all the time. Basicly I have the ability to pick this motor up for 20 bucks.... so no one thinks its a good idea? Not even as a helper to make rowing a bit easier? Don
Zero carbon and fun to use.
Zodiac 240 : lgh 8 ft/ Motorguide 30lb thrust: wt 13 lbs /battery 35ahr AGM:wt 23 lbs. The motor and battery cost around $100 each. Silent, fun, no fume, zero carbon ,if charged with PV or wind. If your towing the tender you can get away with just removing the battery because the motor is so light weight. Ultimate range on the battery hasn’t been determined. Going 3/4 to 1 mile with the motor set on high appears to drain the battery about 10%. It powers into wind and waves. With 15-mph winds, headway is assured. Gusting to 20+ headway is not assured with the 30lbs of thrust. The more thrust the more versatile the system would be in regards to weather conditions. It depends on how you plan to use it, with reserve for the unexpected. I have been in 20+mph gusts and I could see a limit coming, to unimpeded headway.
Zodiac 240 : lgh 8 ft/ Motorguide 30lb thrust: wt 13 lbs /battery 35ahr AGM:wt 23 lbs. The motor and battery cost around $100 each. Silent, fun, no fume, zero carbon ,if charged with PV or wind. If your towing the tender you can get away with just removing the battery because the motor is so light weight. Ultimate range on the battery hasn’t been determined. Going 3/4 to 1 mile with the motor set on high appears to drain the battery about 10%. It powers into wind and waves. With 15-mph winds, headway is assured. Gusting to 20+ headway is not assured with the 30lbs of thrust. The more thrust the more versatile the system would be in regards to weather conditions. It depends on how you plan to use it, with reserve for the unexpected. I have been in 20+mph gusts and I could see a limit coming, to unimpeded headway.
Consider longer oars
While I would never recommend an inflatable as a row boat you should be able to get a reasonable thrust requirment by estimating the pull you put on the oars. I know that I would have a hard time pulling 15 lb on each oar on my hard dink but could easily get twice that on an inflatable. By getting longer oars you reduce the work when going to windward and against the current. Kinda like putting the boat into a higher gear. By long I mean +8'
While I would never recommend an inflatable as a row boat you should be able to get a reasonable thrust requirment by estimating the pull you put on the oars. I know that I would have a hard time pulling 15 lb on each oar on my hard dink but could easily get twice that on an inflatable. By getting longer oars you reduce the work when going to windward and against the current. Kinda like putting the boat into a higher gear. By long I mean +8'
Going to go with 36 pounds and a trusty set of oars....
Looks like I might have lined up a pretty good deal on a second hand motor and battery so I'm going to go with that and try it out hopefully this will work if not well could use a second battery anyway and who knows maybe a canoe mount down the road.... I have a very easy going admiral
Don
Looks like I might have lined up a pretty good deal on a second hand motor and battery so I'm going to go with that and try it out hopefully this will work if not well could use a second battery anyway and who knows maybe a canoe mount down the road.... I have a very easy going admiral
Don- Status