No kidding, I have had two people that have twin engine fountains tell me that you can go upriver FASTER than downriver. Both said these were GPS speeds. Both have been performance boating for years.

Is this some kind of counter-intuitive phenomenon, or does it provide insight into people that like beaks on boats?

It would seem on gps the fastest speed would be going with the current. With a water pressure speedo fastest speed would be against the current. Does that make sense?

My speedo reads exactly the same up or down river. The river has a 4-6mph current. Gps speeds up river are generally about 5 mph slower.
Maybe the wind was 20mph blowing up river when they took their GPS readings.

my cruiser goes faster with the current on GPS. The paddlewheel reads a bit slower with the current if all of the canvas is up, reads the same if the canvas is down.

Can't imagine any instance where you would actually have a higher SOG when battling the current. Just doesn't make any sense.

You guys need to hit the Niagara River on the lower side by the hydroelectric dams. If you are going up river and slow to a stop the speedo will read about 40mph. Spin it around and the old F311 will run above 80mph. Fastest ever!! It just gets a little dicey when you turn the wheel at 4000 rpm to get it around.... the rock wall comes up real fast.

My Fountain 27 ran about 2 1/2 MPH faster down current on the Muddy Mo on my Garmin GPS and the current was like Griff said.

I would suspect that on a river with very slow flow rate and running with the wind and some chop you might be able to make that happen.

I would imagine GPS would read slower upriver and faster down river.

And the speedo would read the same both ways.

Well, I guess that answers it. It seems to be a unique characteristic of beakboats.

Maybe the beak and swimplatform do something to the satellite signals.

On the ol' Delaware river you can go faster either way , depending on which way the tides running. Duh, no brainer here .

The gps calculates speed over ground so your total should include the speed of the current downstream. Sorry