MacGregorSailors.com

Ok so I got a thruster for a 10" and up prop which is as big as he lists but reading the literature it appears you can buy a bigger one (special order), any way put the thruster on the dinghy which has a 15hp honda 9 3/4" prop and had some scrap stainless and made one 15.5% bigger for the Mac.

15.5 % because that was as big as I could get out of the scrap.

Tried them out today on the dinghy first with substitute load and the wife and thought it was going slower until I checked the plotter which said 32 kph but it makes the motor very quite and very good to steer so the wife jumped out and I got up to 42kph but it seemed like the nose was up like it wasn't planing properly even though going faster than ever 6-8 kph.

Took the Mac out without the thruster lightly loaded and it hit 15.7 knots and running at 5500 rpm on the big prop,
fitted the thruster and yep it made it quieter? but only revved to 5400 rpm and 14.5 knots trimmed it to full and the nose came down and it went to 16.9 knots and rpm stayed the same.

Trim has only ever made a very small difference without the thruster and it was still climbing when I ran out so maybe it could benefit with a shim? and this could explain the nose up attitude of the dinghy as I still had two holes to go but that was where it always planed best prior, unfortunately by the time I discovered the trim on the mac the dinghy was packed up and couldn't test it.

Filled the ballast and got 14.3 knots at about 5250 rpm on the Mac.

The most impressive effect was the quietness and the steering response, absolutely magificent even when coming into dock without the motor running had way more control.

All up am more than pleased and now looking forward to testing for economy which should be good as it was doing 5.3 knots a 2000 rpm and absolutely purring at all speeds.

I don´t have the thruster but I have some experiance with the Dolphine Hydrofoil.
After having them installed for many weeks crusing happyly with them I decided to make a comparison test. I was motoring with and without the foils, same day, same water, same load, same direction, same RPM, same mood, no wind, no seastate. My result was (repeating it several Times): with the foils about 1 kts slower than without, with/without foils no significant change in attitude of the boat on the water surface by changing the tilt.
I don´t understand that reading some inputs of others, might be my instruments are to honest .
My foils are for sale now http://cgi.ebay.de/ws/eBayISAPI.dll?Vie ... :MESELX:IT
Rainer

Rainer

They may not be much advantage on a flat bottom boat like the X , But on my which has a 17 deg deadrise I beleive it will help get the boat on a plane faster & plane also at a lower RPM allowing you to cruise at a higher speed & save on gas

The M has I beleive a 15deg deadrise & I think it would also help them !

J

Rainer
We had hydrofoils on the dinghy and think they did make some difference but I was comparing the thrusters to the dinghy with the hydrofoils on (forgot) so I guess that makes it better again, where the hydrofoils helped on the dinghy was to bring the nose down under heavy loads but when really overloaded and/or in rough water nothing would get it on plane and maybe that is where your is?
The more I think about it the extra trim I had left could have helped a lot more but it has been pinned there for years and never even thought of it until I saw the huge difference on the but on both boats the steering was far more precise.
Must admit I didn't expect much but was hoping for an increase in economy more than speed and didn't even think about steering.
The best I ever got out of the dinghy even with hydrofoils and lightly loaded was 36kph so 42kph loaded is excellent and it is a relatively flat bottom V nose punt.

Note the readings on the dinghy were paddle wheel on the fishfinder and the was on the Raymarine chartplotter (GPS setting not paddle)

I just rec'd my Power Thruster and will do a non-scientific Before/After report as soon as I can launch. The weather at 8,000' in Colorado is not co-operating yet. And YES, Bert will take it back if it does not perform as advertised

Bob

Bob
Can you test it at different RPM ranges before and after too as I was just in plain too much of a hurry with light to do more than WOT but think you will find trim makes a huge difference and might pay to check this before and after too.

Looking forward to your results, I presume this is the standard size 2?

I had the cavitation plate pre drilled and only had to smear some Duralac and put some tape on, note would pay to have a battery drill to run through the tape and a knife to cut the edges.

Bob

I just received mine this week. I'm actually on the way out the door now to install the power thruster and a replacement fender. Weather permitting, I'll test the thruster out on Memorial Day Weekend!

Jim King has one on Konig and has been pleased.

I take the fuel savings and increased thrust promises with a grain of salt. Even a minor positive change will make me happy!

Doug

Doug
Yeah that was my take to on the claims but just on what I have got it's not far off it with extra power/speed so will be interesting to see what the economy is although there are too many variables with wind,tide,load etc to know for sure.

Would also be interested to know whether the standard size (10" up) is better or if it should be larger to suit our larger props.

Bob

Bob/Doug,
I plan to pre-drill my holes and bring my battery drill. Since I have a 3 x 14 x 9 Hydrus prop I had to return the #2 originally sent to me for the largest size PT and had to modify that one by standing on it to spread it out to get the 1" clearance. To further complicate matters I am switching out the Hydrus after my first test runs for a stock aluminum 3 x 14 x 9 to see if I can get any more RPMs at WOT. Since I am at 8,000', my E-tec 60 is only putting out 45HP so my speeds won't relate to anyone at sea level. Currently my cavitation plate is as high as it will go and the transom trim is full "IN". I am hoping the PT will stabilize my steering at lower speeds.

Bob

I installed my PT this evening! It came with mounting instructions but not positioning instructions. I may be a bit too far back. I spent time making sure they are even and straight! Can't wait to her back into the water! I measured from the center of the hub to the furthest point of a blade, multiplied that number by two, rounded up a 1/4" and ordered the PT from their website.



I'm tinkering on the boat in and around working through a massive honey-doo list. Got my replacement fender mounted today too!

...Doug

My instructions say the middle of the top of the thruster should be in line with the centre of the prop, it is on the Mac one but slightly forward on the dinghy so I could use one of the old hydrafoil holes.
I notice on the dinghy the forward edge of the thruster lines up with the centre of the prop.

When I was installing mine I called Bert on my cell and he told me the tip of the prop should be at the mid point of the PT, which actually ended up with the center of the prop housing at the mid point of the PT. The critical mounting is the 1" clearance of the prop tip to the PT. If you end up with less than an inch you can put the PT on the ground and step on it bending it to perfection (as per Bert). The instruction sheet should have pics for install challenged peeps like me.

Bob

Does antbody have information if mounting the PT is voiding the E-Tec warranty?

The two owners who recently installed a PT, what is your experience regarding gas and performance?

I'm still sitting on the fence on this one, it sounds to good to be real.

I would really appeciate your feedback to these questions.

Thanks

Obelix

Sorry about the testing delay--had to be away from the boat but my initial install with the Hydrus prop gave me 5,350 rpm and seemed to be quieter at max rpm. The bow seemed to plane out flatter as well. I will attempt to begin my testing this week if the weather permits.

Bob

Doug W,

You got the closest setup compared to myself (2008_M, 60 E-Tec), what is your initial experience regarding efficiency, handling and economy?

Do you feel it is an addition worth doing?

Thank you for your opinion.

Regards obelix

BTW congrats to your Website, it looks great.