This weekend my friend had me ride in his boat to see if an improvement could be done to his rig. So here is his set up 18' Lund fisherman, with a merc 125hp, boat and motor are both 2002 model year.
WOT 4800rpm
Max WOT 5250RPM
Top speed 36mph
Prop merc black max 21P
gear ratio? I couldn't find it anywhere its either a 2.07 or 2.33(something close to that, see it could be in that ball park online, but cant verify)
According to mercs prop finder that motor only option is a 2.07, the theoretical speed is 46.1mph putting slip up to 22% That don't seem right. Any help on the gear ratio would be great.
The boat hole shot feels good, it is sensitive with trim once at speed, more than other boats I been in.
Something I did notice, the edges of the prop were like eaten away, not gone but easily seen when looked at close. It isn't from running shallow as the paint is still on a decent percentage of the edge all the way to its tip, its actually like eroded. I have heard that a prop can create a vacuum void and boil the aluminum edge away, I never seen it pointed out but it almost looks like what I think could be here. I am not saying it is but it isn't sand wearing the edge down. His prop is pretty darn good shape for being 12 years old, only a few very minor dings.
So any info on if you believe the slip can actually be 22% and what's causing the issue with the edge of the blades. The hull is perfect, the bottom is clean, motor runs like a top. Something doesn't seem right.
Thanks
WOT 4800rpm
Max WOT 5250RPM
Top speed 36mph
Prop merc black max 21P
gear ratio? I couldn't find it anywhere its either a 2.07 or 2.33(something close to that, see it could be in that ball park online, but cant verify)
According to mercs prop finder that motor only option is a 2.07, the theoretical speed is 46.1mph putting slip up to 22% That don't seem right. Any help on the gear ratio would be great.
The boat hole shot feels good, it is sensitive with trim once at speed, more than other boats I been in.
Something I did notice, the edges of the prop were like eaten away, not gone but easily seen when looked at close. It isn't from running shallow as the paint is still on a decent percentage of the edge all the way to its tip, its actually like eroded. I have heard that a prop can create a vacuum void and boil the aluminum edge away, I never seen it pointed out but it almost looks like what I think could be here. I am not saying it is but it isn't sand wearing the edge down. His prop is pretty darn good shape for being 12 years old, only a few very minor dings.
So any info on if you believe the slip can actually be 22% and what's causing the issue with the edge of the blades. The hull is perfect, the bottom is clean, motor runs like a top. Something doesn't seem right.
Thanks
