Power Thruster Test Results

[bscott]

2001 , 60hp E-tec @ 8,000' (45 hp equivalent at 8,000'), 3x9x14" std. alm.prop, no wind, no waves.


2,000 w/PT 4.8 kts--w/o PT 4.8 kts--w/PT/ballast 4.8kts
2,500 w/PT 6.2 kts--w/o PT 6.1 kts--w/PT/ballast 6.2
3,000 w/PT 7.2 kts--w/o PT 7.1 kts--w/PT/ballast 7.0
3,500 w/PT 8.7 kts--w/o PT 8.3 kts--w/PT/ballast 7.6
4,000 w/PT 10.0 kts--w/o PT 9.7 kts--w/PT/ballast 8.6
4,500 w/PT 12.0 kts--w/o PT 12.0 kts--w/PT/ballast 11.0
5,000 w/PT 14.0 kts--w/o PT 14.0 kts--w/PT/ballast 13.0
5,300 w/PT 15.0 kts--w/o PT 15.0 kts-------N.A--------

The standard OEM 3x9x14" prop = 5,300 rpm. the Hydrus 3x9x14" = 5,150 rpm., no ballast.

The PT was quieter at all rpms however the steering effort seemed heavier. In mid ranges I could tilt the engine up a little to get more rpm at a given throttle set, however I had to tilt max "in" from 4,000 + to get the bow down.

I had toyed with the idea to installing some sort of keel to stabilize the tracking of the under power but the PT tracked straight even bashing thru waves. Excellent maneuverability at the dock.

I can't report on fuel economy but I did run 2 hrs at varying speeds on 3 gallons.

Given the bright stainless steel color of the PT I would be concerned about river monster/bull shark encounters as it is one big mother of a flasher.

I would definatly recommend the PT for small proped boats having trouble at the launch ramp/docking. Time will tell about fuel savings.

On another note, if I were to power boat all day, I think the steering would be easier if I pinned one of the rudders "up" as there seems to be alot of tension in the rudder system while hooked to the engine.

Bob

[Obelix]

Thank you for the numbers bscott.

It appears there is no appreciatable speed difference with or without the PT over most of the RPM range.

If I understand you correctly, the main plus is the better tracking of the boat with the PT mounted.

Do you or has anybody else any info if mounting the PT is effecting the engine warranty?

Cheers

Obelix

[Threms]

What kind og PT is it?

one like this http://powerthruster.com/ ?

Daniel

[Catigale]

On another note, if I were to power boat all day, I think the steering would be easier if I pinned one of the rudders "up" as there seems to be alot of tension in the rudder system while hooked to the engine.

Bob - both of the rudders should be up above hull speed (6kts or so) under power. They are not designed to take the loads at speeds above this and will break either the rudders or the steering gear.

[bscott]

Steve--Both rudders are out of the water however I noticed that there is a fair amount of friction due to the rudder lines holding the rudders up. Once I eased the lines off a bit, the steering became easier. I ran out of time otherwise I would have pinned one rudder up with the nut and bolt to see if it would relieve the line pressure and ease the steering. I don't power that much so it has not been an issue until this testing.

Threms--that's it.

Obelix--1) better straight line cruising and slow speed manuverability, 2) less engine noise
I don't know why it would void the BRP warranty.

IF the fuel savings claim is true, it will be worth the $$$.

My grandkids hope the big flasher on the back of the boat will attract more fish

Bob

[Catigale]

Ah...I see. Sorry for the waste of bandwidth.

[Threms]

however I noticed that there is a fair amount of friction due to the rudder lines holding the rudders up. Once I eased the lines off a bit, the steering became easier. I ran out of time otherwise I would have pinned one rudder up with the nut and bolt to see if it would relieve the line pressure and ease the steering.

Threms--that's it.

Your right, i tigthen them, then loose them back 1/3, it helps. Its a h e l l of a job to put inn the nut when the boat is in the water, i tryied, and it helped alot.

But the steering works best whithout the engine in the system, so i can follow your idea. If i didnt power that mutch, i would find a smaller engine and a stick.

Daniel

[sbods]

I am keen to hear if the PT really does make the fuel savings it says that it does!

As for the tight sterring with the rudders up.... I once tried/tested motoring with the rudders up but VERY losely tied off.
After a short run and a couple of turns there was an almighty bang and the engine rpm coughed downwards.
I looked behind to find one rudder "floating" with a big chunk ripped out of the leading edge where it had dropped into the water and caught the prop.

Guess I will not do that again in a hurry!!