KC
Just wondering, thinking aloud, but with the water splashing up and flowing out high up on the motor (in the pic) might it be a plan to fit the new prop with the motor at its present height rather than dropping the motor perhaps for no benefit?
If the prop slip is reduced with the 4 blades and the grip is better perhaps a trial with the motor where it is might prove instructive... thoughts?
Chimo
I'm not so sure Chimo. Although there is a lot of splashing going on, the AV plate seems to be well above the water - looking at it on the phone at least.
kc, can you trim the motor so the AV plate is parallel to the keel, then use a straight edge off the keel and measure up to the plate (and take a pic)? This will be a good 'guide' of where you are currently at.
Also, what shape is the very bottom of the boat/keel? A vee, or some sort of keel shape (from the rotomold) that provides extra protection to the hull? Pic of this from behind too would help too.
Cheers
PS. From what I recall of reading G2 300 threads over the last 6 months or so, they referred to 3 different prop types being used. RX4, REV 4, and a Bravo 'something' (can't recall if a 3 or 4 bld.
Can your mechanic get hold of a REV 4 17" or a 19 to try Kev? 19 maybe too big though I think. These work great at high mounting positions.
2 day trail and this pic is with the RX 4 18. The 3 blade Rebel 18 was really unsuited, perhaps in part because of motor height but was slipping very badly. This shot and the 2 days with the RX 4 is still with significant prop slip and cav plate is a good inch and a half to 2 inches above water when running at 50 k's. I still have the Rebel here so can give it a go if need be with the motor set deeper but on advice the RX 4 is the right prop for this style of hull. Will be dropping engine 1 hole to start with and can always go down another if needed but I think 1 hole down will be "the business'". Current numbers are good but with full bite of the prop should be even better. I will get a few more pics as suggested of boat on trailer.. Some of the "splashing" is coming of the brick of a thing that is the 1kw Furuno transducer. I have a spray cover coming.
Kev
Some pictures and Measurements. Cav plate is sitting 15 cm above bottom of hull in horizontal trim. Seems too high. a 4cm gap between top of prop and cav plate puts tip of prop 11 cm above hull.
Wholly sh!t, is that with the plate parallel to the hull keel, or trimmed in a little ? Bit hard to tell in pics.Originally Posted by kc
But yes, too high regardless.
Plate is at 90 degree to hull. From what I am able to read and what advice I can get online from the experts , because these are set back some 10 inches from the hull, almost like on a little "pod" they are supposed to be mounted higher, but IMO, just not THAT much higher. The shot of it running and all the white water/foam flying around under the cav plate says it for me. It is catching air, lots of air, and I am expecting significant improvement in performance when it is just grabbing water. I have posted the measurements and images on the etec owners Gen 2 page as well. A few of the guys there are really on the ball with these things and have given excellent advice and feedback so will see what they have to say.
kev
Sorry. Didn't post this.
Kev
Didn't realize the transducer splash impact ( cover plate should remove this confusion) but with the pics now shared it does appear the motor is a tad or maybe 2 tads too high. Easy to adjust up or down especially with the G2 rigging anyhoo.
Cheers
Chimo
So you mean 90 deg (right angles) to the transom Kev, i.e. trimmed right in? If this is the case it will inflate the distance, probably why you got 150mm.
What I am looking for is the parallel distance, i.e. hull bottom (keel) horizontal (with a spirit level), and A/V plate also level, then straight edge to transom and measure up from keel.
Yes true. 'General' rule is 1" higher (than you would otherwise mount) for every foot you set back with a pod.
Cheers
Yep, sorry, not 90 degrees. Image is taken with motor trimmed out so that cav plate is parallel to hull/planning surface. Trimmed right in the engine cav plate sits higher so I think the position is about right. Feedback seems to be drop 2 holes. Waiting for the main guy (Huey) on the etec owners site to have a look but seems to be about 2 holes to drop.
Ok, wow, that is very high.
I don't know the mounting hole spacing on a G2, but two holes would only drop you ~38 - 42 mm if it is similar to other makes... and 110mm still seems way too high.
However never propped or played with the setup of a G1 let alone a G2, so maybe Ocean Spirit or Scottar will chime in with suggestions too.
Hi, just catching up on this one. What RPM did it pull at WOT with the RX4 and trimmed out? Keeping in mind it is an out of the box engine and will loosen up with hours. I don't think you are too far off height wise if you intend to run the RX4, but no harm in dropping a pin and seeing what it does. Every boat is different. But as a direct comparison to the old G1 on the Seafarer, we ended up 2 pins higher.
I did find the G2 threw a bit of extra water up at 3000-3500RPM when trimmed in with the 3-Blade Rebel/Viper. The gear case componentry is heavy duty to say the least over other production engines in the same HP category.
Stick with the RX4 if you can pull the RPM - it's an excellent prop. I found opening the VVT holes helped too. The G2's are a whole different animal to dial in.
Thanks mate, getting 5500 with the current set up but if I try to really trim out the prop blows out and loses traction. I think the RX 4 will be the prop but I am sure I have to lower the engine a bit, that said everything I am being told by the experts if to run the motor high. Dealer is a good bloke and only 3 k's up the road so he seems happy to help me keep tinkering to get this right. Should done Tuesday and have another run Tuesday arvo.
Kev
If the current problem can be solved by dropping just one hole kc I will be super impressed. Hell, even if it is solved by dropping two holes I will still be impressed!! [emoji1] . With the top of the prop currently 110mm above the keel, a 2 hole drop will reduce that to approx 70mm +/-. That is still a significant rise up from the keel.
Revs will drop as the slip will reduce a lot when you drop the donk, and the prop can get some bite. Can't recall if you posted the speed at WOT, but did you work out the slip kc?
Depending on how much the donk loosens up with hours, you may need to consider a size down in pitch, as I believe it is recommended to get 5800/5850 with your normal loaded trim - which for you will be pretty heavy kc for your big runs.
Cheers
Thanks gofish. Top speed at WOT is 70k's with not much trim. Prop pitch is certainly on the radar when I drop the motor. Dealer is really happy to help me tinker with this so will see how sea trails go this arvo and maybe get an RX 4 16 up so a try.
Kev
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