342 w/350 MAG Hill Marine prop update

Black_Diamond

figured I would start a fresh thread for future searches. 

Had part of a day to play with the Hill Marine 4x4 20P props on my Bravo 3's.  For reference, I changed from the Merc 22P props. 

Acceleration: From idle speed to plane: drastically improved and very smooth. Almost no digging of the aft, very little bow rise. Tabs down/drives down. Very noticable acceleration while on plane too. 

Planing: little to no drive trimming needed. Was able to stay on plane at ~21mph w/o tabs. Again, very responsive accelerating from 21-30 mph. Interesting the wake behind the boat from the props is smoother looking too. Speed vs rpm I found no loss from before. Still need to make a WOT run. 

Coming off plane:  342 owners know of the swimplatform wash.  I still have that but it is MUCH less. The aft does not dig in like it did before. Idle speed / no wake speed is good at ~5mph. With the less churn from the props I can even pick up the speed at bit too. 

Docking:  For the first time the boat will truely 'spin' on point. Low speed response improved.  A definate win. 

Engine sound:  This was a big suprise. The engine noise at plane is WAY down. Easily have a normal voice conversation now. Obvioulsy working less hard.  Sounds smooooth. 

I'll add more info as I get it. Might be the best $ I spent on this baby.  lol. All thanks to this forum or I would have never tried them. So +++ to the guys who posted on these this year!

Some VV mobile screen shots to follow.  

Black_Diamond

VV mobile shots

laureniac1

I'm telling you the Hill Marine family is growing lol! I actually love my 270 again. So worth the buy

J3ff

The drastic noise reduction was the biggest surprise over here too

Handymans342

Need before and after GPH

Black_Diamond

I was running 1.1-1.2 mpg.  Per VV

previous my calcs were in the .8/.9 mpg range. 

Handymans342

Now that's a big deal

Dream_Inn

It's great to hear the props are working for you.  I've been talking with another 342 owner in marina and he wanted to know the exact details of what/where to buy.  I may send him your way BD.

I just finished over 400 miles in the last 17 days on my hill marine props and gotta say they are fantastic!  My wife commented a couple times on the trip how much quieter it is and noticeably quicker getting on plane as well as a smoother ride.  & over a 100 miles were in the ocean.

davidbrooks

BD hopefully i will be back on the water this week.  I have the 342 wtih the 350 mag as well.  The difference though is that i had Merc 3x3 24p that i swapped out for Hill 4x4 22p at thier recomendation.  Anxious to see how it handles.  Your info is great news.

reneechris14

Now that would be nice to compare hill marine  20's to hill marine 22's. My 270 had a though time with stock 22's put the hill marine 20's 4x4 made a huge difference. Now my 342 comes up really well with stock 3x3 22's, but I know there's a lot of prop slippage from say 12mph to 18 mph, the 4x4 grab so much better. Also cruise speed at 30 mph 4000 rpm is (both 270 and 342) still a 18% slippage. My goal would be to cruise 28 mph 3600 rpm and still have a great hole shot.

Black_Diamond

Will be nice info to compare too. 

My 342 does have the 'older' transom that is stepped in further. I'd bet the newer ones might perform a bit better with the drives further back. Plus a bit more hull in the water. 

davidbrooks

BD we both have the 2003 342.  

DanD2

I would imagine the same gains would be had with a Volvo setup??? I noticed that Hill Marine offers the 4 b prop for the DP

Michael T

@Black_Diamond. Where do Hills put your WOT?

Black_Diamond

I need to get out and get WOT #'s yet. Need a smooth lake day!  lol

Michael T

@Black_Diamond, I hear you. My only concern given your data stream is that your WOT RPM might be over the specified range. Not trying to be a dork but a friend had a similar data stream and found the quiet and smoothness put him at too high of his WOT RPM. Experience, okay old age, has taught me there are very few free rides and Rinker usually has their boats propped pretty near their best performance. Fingers crossed that your WOT RPMs are fine!

Black_Diamond

We'll see. Hopefully not too high.  I had 24P from the factory. Way too much pitch.  22P helped alot, but I was still below the low limit WOT numbers. 

Handymans342

@Black_Diamond, what are your WOT range numbers?

reneechris14

I have stock 22's And I have hit the 5G mark,but not for long.

davidbrooks

So what is going to be interesting to me if i ever get back on the water again is what happens to me at WOT.  Before i had stock 24p stainless 3x3's and could never go above 4500 rpm no matter what.  Getting up on plane was a struggle with 4 or more on board or 3 or more barnacles stuck to the bottom.  Staying on plane meant a constant juggling with the throttle to keep it at 23+ mph.  Anything under and i would fall off plane.  Seemed like the only speed i could maintain was 25-27 mph.

Black_Diamond

@davidbrooks. With my original 24 props, the boat was a disaster with anymore than 2 people, even that it struggled. Poor docking handling too. I somewhat blame them for trashing my 2 outdrives too.  Low to mid 4,000rpm if My memory is correct. lol

the 22P was certainly a game changer, better low speed handling, much improved planing time from before, bit it still was work to get going with another 2-4 people.  Still could not stay on plane below the 27/28mph range. 

These 20P 4x4 are a radical improvement. Hopefully I'll hit right around 5,000 rpm at WOT.  

Michael T

@Black_Diamond. Trying to figure-out how your boat could have left the Rinker factory with props that were such a mismatch. Did you purchase the boat new from Rinker - (I'm wondering if a PO could have swapped the props)? Second, with the original 24"pitch where did your WOTs fall?  Was the diameter of all three sets of props the same. While I'm at it was there a change in the rake or cup of any of the props - as changes in these specifications can make a huge difference.

This is very a interesting discussion to me. I have had many Rinkers from the smallest to the largest hulls. I have lost count of the props I have tried on different models. I don't remember ever getting significantly better performance from any prop swap unless changes in diameter, rake or cup were involved. 

I did get rides with a bit less vibration and maybe a 1-2 mph top end increase by having SS props blueprinted.

Most of the time I got either squirrelly performance (like from the old high five props) or WOT RPM numbers that were bad for the engines. That is why I would load the boat I was testing to its normal/usual load then go right for WOT as IMO WOT tells it all.

Of course, I have had friends with cruisers DELIBERATELY "under prop" their boats (too high a pitch) to get better acceleration and a smoother ride. As we all know this will burn more gas and one has to be very careful to not exceed the RPMs at WOT with this configuration and over rev the engines.

My bigger concern with re-propping an engine is to create a situation via pitch, diameter, rake, cup or a combination of the aforementioned that places the engine WOT BELOW the engines specified WOT range, because as we know this creates lugging which is really harmful to the engine and drive train.

In your case it would be over revving that I would be looking for.

I will be very interested to see where your engine's WOTs end-up.

Carsnmorellc

You have me second guessing getting my 22P Hill Marine Props and thinking I should have went with 20P.  We will see Friday when I take her out for the 1st time.

Michael T

• @Carsnmorellc.....don't worry until you perform a WOT range test. That will give you a major piece of information. Will be interested to see where your WOT falls. Good luck, MT

Dream_Inn

MT, a lot of 342s I've ridden on have problems getting on plane and then staying on plane.  The big difference here is switching from 3x3 to 4x4.  It has made a HUGE difference on my boat as well.  I also wonder if I should have changed pitch just a bit more, but I think it is ok.  Right now I'm getting 4600-4700 rpm switching from 22p to 21p (but 3x3 17.5dia AL to 4x4 18.5dia SS).  Most boat manufacturer's go with one brand of props and the average prop that will be fine for the boat.

Black_Diamond

@MT:  I bought the boat new, so the 24P were from the factory.  Al mentioned to me long ago some left with 24P some with 22P.  All I can say about the 24P was the boat was a disaster to get on plane within a few MILES at times with 4 adults on board.  WOT was definitely 400+ rpm too low (had screwed up tachs at the time too).  My 22P were WOT between 4,600-4,800 rpm, still low or at the very low end of the WOT numbers from Merc.  The 24P and the 22P were standard Mercury B-III props.

The B-III prop diameters, at least the Merc ones are all the same diameter.  All you can vary is pitch.

Hope I can snag WOT numbers this weekend.  I'd like a calm day so the waves are not a factor.  I'm shooting for 5,000 rpm   Looking at the numbers I have at cruise with the 20P, I'm not too worried about over revving.

The engines sound amazingly happy.

http://s201.photobucket.com/user/Black__Diamond/media/Video_Aug_26_4_27_46_PM.mp4.html

Video link, hard to quantify, just listen to how quiet it is.

reneechris14

my previous post said 4600 to 5000,but this says 4800 to 5200, there also is a rev limiter on the pcm555 or so i believe. Like I said not looking to go 40mph just like to stay under 4000 at a good cruise speed. I dont think anyone would like to push a motor over 5000 rpm for to long but nice to know you can max it out

Handymans342

Yeah, it aint a diesel LOL

Black_Diamond

WOT: 4,900 rpm. Good number.  

Handymans342

Yeah! What was the speed? 

Black_Diamond

~37 mph.  

Cruise at ~30 at 4k rpm.  

Calling it a win.