Top Speed Question

[Tx 201]

We have all asked, responded to and worked over questions about what prop, JP, RPM, and PSI for max speed. I have just one more question for everyone:

When posting top speed, how far do you run to settle on your top speed? I have had more than one mechanic tell me that my motor will require about 2 miles once I am trimmed out for the prop to fully bite and get the lowest slip resulting in top end speed. This is a straight run, as any turns on the lake or river causes the boat and prop to lose a little bite, and then has to catch up again.

I usually hit it, trim up and once I am at max rpms, looked at the GPS for speed. The lakes around here it is impossible to get a straight run that far. What does everyone think?

[AlanW]

Tx, I'll give a different prospective on this than most will have. I don't tournament fish like most on here, so I'm not racing anyone for miles to get to a hot spot.

So, for our impromptu-for bragging rights-local Sunday sandbar races, (which we do a lot) the race is well over by 2 miles Might air it out for a mile at most.

Most of the time, I'm on the river, so like you, I'll hit it hard, get to max rpms, and go about 1/4 to 1/2 mile after that, check the GPS for top speed, clear it, then turn around and do it again back the other way.
Hole shot and great mid-range acceleration are probably more useful to me than that last 1/2 mph top speed way down the river

But interesting question! Now that I , I'll and see what everyone else says.

[illinicobra]

I've ran 5 miles and I've run it the same for 1/2 mile. I don't think it takes 2 miles, but depending on the set-up it might take a little longer to get to full speed. My 3-blade takes longer than my 4-blade at the same settings on my jp. Just like everything else with boats, there not all the same and all perform differently.... Also conditions are very rarly the same.

[tom h]

Last time I tested props and jp height I was on a small pond, probably less than 2 miles long, I got up to about 66 quickly and just inched up a little at a time until I ran out of lake at about 72, I think I could have got a bit more if I had a longer run.
97 201D
99 225 efi
10" slidemaster
26 tempest plus
3.5 below pad(I think)

[Joe S. King Cobra]

I generally hit my top speed before I take the boat off the trailer.

[MigAz]

The only time I have I got my boat to it's fastest speed, it was between 1-2 miles after a warmed up blast off. The boat attained a lift like I had never experienced. It seemed to "release" and literally take on a compeletely different feel. You could argue that once the turbulent flow has settled to what is called laminar flow (I won't bore you w/ fluid dynamics) that it is reasonable. Enter you, the driver, adjusting to wind currents that come into the equation, then yes, I think it's safe to assume that you achieve the maximum speed within this distance.