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XCR-700 · 09-09-2009, 02:29 PM

The numbers on the graph are interesting, and leave me asking what kind of boats were talking about and how the MPH is being measured.

I think you also need to consider how stable your boat is at minimum plane speed. i.e. will it fall of plane if the engine RPM varies at all or if you hit any wake, or correct direction.

In my mind minimum plane speed is the speed where my hull is up "on top of the water" and will stay there without me playing with the throttle every second and/or holding a dead straight path across flat water.

In real world conditions, engine RPM will vary 100-200, you will hit someone elses wake, and you will have to make directional corrections and that will all effect the speed at which the hull will stay on a plane.

For my current boats:

1988 Glastron Carlson CVX-20 w/225 Yamaha 2/stroke outboard the lowest speed it will stay on top is like 32 MPH

1989 Glastron Carlson CSS-23 w/Mercruiser I/O the lowest speed it will stay on top is like 28 MPH

In both cases thats with average loads (people and gear) and near full fuel tanks and using GPS.

I have to question if the majority of the folks responding are talking about very small boats (under 18') with light loads and borderline falling off plane, AND using some factory speedometer (NOT super accurate) as I just dont see a whole lot of boats that can hold a solid plane under 25 MPH and most that I have driven are closer to 30 MPH than 25 MPH.

Well thats my observation

GH

p.s. the 25 MPH exactly option seems like a useless number in my mind as no boat holds and exact speed for very long, grab a GPS and see for yourself! I think you should consider re-polling and split the groupings into 5 MPH chunks and better define the term plane to include the factors I have described above.

09-09-2009, 02:29 PM	#8
XCR-700 Senior Member Join Date: Sep 2008 Location: MA Posts: 1,333 Thanks: 744 Thanked 533 Times in 310 Posts	The numbers on the graph are interesting, and leave me asking what kind of boats were talking about and how the MPH is being measured. I think you also need to consider how stable your boat is at minimum plane speed. i.e. will it fall of plane if the engine RPM varies at all or if you hit any wake, or correct direction. In my mind minimum plane speed is the speed where my hull is up "on top of the water" and will stay there without me playing with the throttle every second and/or holding a dead straight path across flat water. In real world conditions, engine RPM will vary 100-200, you will hit someone elses wake, and you will have to make directional corrections and that will all effect the speed at which the hull will stay on a plane. For my current boats: 1988 Glastron Carlson CVX-20 w/225 Yamaha 2/stroke outboard the lowest speed it will stay on top is like 32 MPH 1989 Glastron Carlson CSS-23 w/Mercruiser I/O the lowest speed it will stay on top is like 28 MPH In both cases thats with average loads (people and gear) and near full fuel tanks and using GPS. I have to question if the majority of the folks responding are talking about very small boats (under 18') with light loads and borderline falling off plane, AND using some factory speedometer (NOT super accurate) as I just dont see a whole lot of boats that can hold a solid plane under 25 MPH and most that I have driven are closer to 30 MPH than 25 MPH. Well thats my observation GH p.s. the 25 MPH exactly option seems like a useless number in my mind as no boat holds and exact speed for very long, grab a GPS and see for yourself! I think you should consider re-polling and split the groupings into 5 MPH chunks and better define the term plane to include the factors I have described above. Last edited by XCR-700; 09-09-2009 at 09:25 PM.