Rpm to mph

[Scubdude]

I need to know how many rpm's should I be running to go at least 3mph with my Johnson 115 hp jet motor. I need to troll 3 mph to have my fishing rig work.

 

[steelespike]

I think a gps will be the best way to determine the rpm.Load,wind and current will affect your result.
Some cells have a gps app.

 

[Frank Acampora]

That is a very difficult to impossible question to answer! RPM vs MPH depends upon the engine, hull, jet impeller installed, and overall efficiency. You need a GPS and you need to develop a chart for all RPM ranges on calm water or the area where you intend to troll. In the end, you may still need to hang a small kicker on the back for trolling purposes because Jets are notoriously crappy to steer at low speeds..

 

[Scott Danforth]

to maintain 3mph, your RPM will need to vary with current, wind, and a bunch of factors. as many stated, download a GPS app for your phone. Frank hit it on the head, you may need a kicker because at 3mph, your jet will most likely not respont to steering inputs.

 

[ondarvr]

I need to know how many rpm's should I be running to go at least 3mph with my Johnson 115 hp jet motor. I need to troll 3 mph to have my fishing rig work.

With a jet there is no correlation between RPM's and speed, it can run at 5500 RPM"S and not be moving.

 

[MTboatguy]

I would not even attempt with a jet, no real way to use it correctly to troll at 3 mph, you need to pick up a trolling motor for your set up.

 

[steelespike]

I know nothing of the details of jets except backing is difficult.
Use a gps and see if it will troll evenly.
I have a feeling that the lower unit of an outboard adds certain extra control you don't find with a jet.
A little drag when seas push from astern, a little lateral control when seas or wind push off course.

 

[ondarvr]

You can troll OK with a jet and control isn't much of an issue, just different. Most people don't troll with them though because kickers are very common on these boats and much nicer to troll with.

 

[MTboatguy]

Depending on conditions, jets can be really bad on fuel, trying to troll with one could get pretty expensive.

 

[ondarvr]

Depending on conditions, jets can be really bad on fuel, trying to troll with one could get pretty expensive.

They are pretty bad on gas.

 

[Bondo]

Ayuh,.... Just like a prop driven boat, use drift socks to control yer trollin' speed,....