Dinghy motor suggestions
I have a 9' inflatable floor dinghy and currently use a 3.5hp Tohatsu 4 stroke. It works fine for getting us from boat to beach but it is a dog when it comes to speed with more than a person in it. I can get it on plane with just me in the boat (175lbs) but anything else it won't. And when on plane it seems like the prop struggles to grab once i get up to full speed and then I have to throttle down and then get back on plane only to have it happen again. I'm curious what causes this? Could it be the cheap plastic/resin prop that comes standard on these motors? I thought perhaps there was flex at higher speeds/rpms. Or maybe its the short shaft length?
I'm not looking for miracles as I know it would require getting a different motor but just suggestions on what might fix my challenges if anything. First I would like to fix the planing issues when at full speed. Second I would like to have a bit more thrust to get this thing moving when it has more than just me in it.
It comes standard with a 7.4" x 7 pitch 3 blade plastic resin prop. I'm curious if switching to the moderate duty resin prop they offer would remedy my issues (5.7 pitch prop). THey also offer an aluminum one which is a 6 pitch prop.
Let me know what you think.
Comments
Me, I'm content to put around at 5 knots because 90% of my dinghy use is within speed limited harbors.
Andy
What kind of dinghy do you have?
I have had the same problem.
Thought it was the prop etc...
Is it a RIB or a vinyl air bottom with a inserted plastic/air/or wood floor?
If it isn't a RIB bottom, the boat bottom will flex with the additional weight
just enough to throw the motor out of plane. This will cause the motor to
cavitate. You will then slow down to drop the revs and again try to accelerate on plane and have it happen again....RIB's are hard bottom and don't flex.
PC BYC, Holland, MI