Motor set up, Props, Foils.

**cwcarter** · 15-07-2016, 02:19 PM

I see recently on here a few threads of motor height and set ups not behaving like they should and I'm just in the process of this as well and thought I'd share what I have done so far.

So new Merc 115 CT fitted. This is mounted at standard height from the installation manual..cav plate even with bottom of boat.

First tests at this height were terrible. Very rough, porpoising, bow high. I had the family (3 people) up front and could not go at speed without violent porpoising. Move them out back the porpoising was improved but rode bow high and rough.
I do have bennett trim tabs and using these I can greatly improve the ride, but for testing purposes until the handling is where I want it these are omitted from use. Other problems experienced was very little usable trim and slow to plain. Just didn't feel right.

Looking at the video below you can see how rough it was with the camera shake, this was the calmest day of testing compared to the next 2 days.
I had to use the tabs to get a max RPM read out the porpoise was so bad.

Running a Mercury Enertia 18P tops were 40mph at 6000rpm.

Motor lifted one hole. Inch above bottom of boat not keel extrusion.
Well its like driving a different boat. Heaps more usable trim, smooth, you can hear it sounds happier. I could get it to porpoise on high trim out. Boat still was bow high getting on plane and at plane also the prop would blow out slightly in chop.

Mercury Enertia 18P, 40mph at 6100RPM.

Getting better but still not happy. I think the motor height is correct and going any higher would cause excessive prop blowout offshore.
Now I was focusing on the weight issue. Being a centre console and most of its weight aft of centre of the hull then you add everyone trying to shelter behind the 1 metre wide console you have a bum heavy boat.
The weight issue is there and there's not much I can do about it. I will not be adding weight up front to compensate like some posts I've read.
I went on the search for a four blade prop and came across a Powertech SFS4 to provide stern lift and more bite.
This prop is a smaller diameter prop then the Enertia and has quite a lot of cupping.

The first thing I noticed with the 4 blade is the smoothness and the lack of clunk shifting. The heavy Enertia clunked and chattered quite well.
Yes the prop did improve stern lift and increased trim range even more. Plaining was easy and this prop holds great but more stern lift wanted.

Powertech SFS4 17P, 40mph at 6000rpm.
Notice the speed and revs are all perfect but handling wise big improvements have been made over the tests.

Happy with prop selection and using tabs for extra lift is great but I find using the the tabs in choppy/confused seas a bit clunky at times and often press the wrong button with adverse effects.
Other things I would like is better slow tracking and even slower plaining.

The next search is for a decent foil. I had an SE sport on my last boat and it was night and day different.
My selection list was between SE sport, True Tracker and Permatrim. After speaking to Scott on here I settled with the permatrim due to being thinner and more fuel efficient at slow speeds.

Yet to trial, waiting for weather to clear.

20160712_171315.jpg 20160712_171337.jpg

**Moonlighter** · 15-07-2016, 03:34 PM

The videos tell the story. Very well done!

Cav plate buried in first one. Cant even see it. Too deep as you say.

Second one you can see it skimming the surface getting splashed. Good height.

Third one the stern lift is, i reckon, evident and the plate is perhaps a touch drier with the 4 blade lift.

You have proven that the attitude and stance of the boat is greatly improved with the engine height positioned like that, and that using the cav plate height relative to the water when running at fast cruise speed is the right method to set this up.

The engine heigh being lifted to correct height does make quite an an amazing difference to the boats performance, doesnt it! The difference surprises many people.

Be interesting to see if the foil gives you that final finishing touch to what you want to achieve. Let us know!

Great report!!

**scottar** · 15-07-2016, 04:59 PM

Originally Posted by cwcarter

The next search is for a decent foil. I had an SE sport on my last boat and it was night and day different.
My selection list was between SE sport, True Tracker and Permatrim. After speaking to Scott on here I settled with the permatrim due to being thinner and more fuel efficient at slow speeds.

LOL. No pressure. Hope it works............

Great write up CW.

**cwcarter** · 15-07-2016, 05:15 PM

Originally Posted by scottar

LOL. No pressure. Hope it works............

Great write up CW.

Haha...yeah I have someone to blame for drilling holes in my motor.

I think I will be impressed from all reports.
Look at all that upward thrust in the videos of the 4 blade going to waste. Redirecting that can only be good.

**cwcarter** · 15-07-2016, 05:32 PM

Originally Posted by Moonlighter

The engine heigh being lifted to correct height does make quite an an amazing difference to the boats performance, doesnt it! The difference surprises many people.

Great report!!

Thanks Moonlighter.
Yes just going up one hole was a huge difference for me. The boat was just unenjoyable the way it was.
It's a must do whether yr boat is new or old.

**Noelm** · 15-07-2016, 06:12 PM

I guess the main thing is to do it all methodically and in order, height is the very first thing to get right, foils and stuff like that are the last things.

**Swanie1975** · 15-07-2016, 06:21 PM

With regards to the chattering issue you had with the enertia prop I'm guessing you have a flo-torq2 hub. Mercury bought out a 2 piece hub setup which greatly reduced the chattering issue and clunk when selecting gear to solve/reduce the problem.

Thanks for posting, some good info there and the vids are great. Best of luck with the fine tuning.

cheers Ryan

**cwcarter** · 15-07-2016, 06:57 PM

Hi Ryan,
Yeah I have the standard Merc hub, the Flo-Torq IV would of made things quieter.
The Powertech uses there own Cushion Lok Hub System.

Cheers Craig

**PixieAU** · 15-07-2016, 08:53 PM

Hi cwcarter, the overlay on your camera... Is that Android? If so, what app please? Looks interesting.

**gofishin** · 15-07-2016, 09:32 PM

Great approach and results cw, good on you. And the 'reward' of getting it right/performing at optimum always makes boating more enjoyable - I agree

. And yep, the Permatim was the better option too, IMHO.
Cheers
Brendon
PS. Post pics of the keel extrusion pls, from behind looking along it, and side-on at the stern, @ keel level.

**Muzza** · 15-07-2016, 10:36 PM

Guys, awesome setting it up like that and getting the performance you were after.

**cwcarter** · 15-07-2016, 10:59 PM

Originally Posted by gofishin

PS. Post pics of the keel extrusion pls, from behind looking along it, and side-on at the stern, @ keel level.

Best Ive got at the moment Brendon.
image.jpg 20160712_171357.jpg 20160710_152526.jpg 20160710_152328.jpg

**cwcarter** · 15-07-2016, 11:07 PM

Originally Posted by PixieAU

Hi cwcarter, the overlay on your camera... Is that Android? If so, what app please? Looks interesting.

I use a Garmin Virb. It has built in gps sensors.

**gofishin** · 15-07-2016, 11:45 PM

Originally Posted by cwcarter

Best Ive got at the moment Brendon.

Was concerned when I saw the top pic, but then realised they filled the end of the keel extn. in.

That is a decent size keel/extrusion, can't do much (to reduce possible ventilation) with that - that doesn't involve a welder, miller, bit of alloy and a good tradie.
Cheers

**cwcarter** · 05-08-2016, 06:10 PM

Had the boat out on Tuesday in some 15 knot sloppy conditions and the permatrim worked better than expected. Made the boat softer riding and seemed to address everything I wanted.
More tests to come on flat water with video to compare.

Thread: Motor set up, Props, Foils.

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