305s...what(39)s your lowest planing speed+rpm???-gctid393176

[Guest]

My wife doesnt like "going fast". I let her know that I'm just trying to stay on plane to maximize fuel economy. Trying to find the happy middle ground what is your slowest planing speed. I believe I can plane at 2900 rpms but I think my stern is digging in a little at that speed.

[Guest]

waynepj3 wrote:
My wife doesnt like "going fast". I let her know that I'm just trying to stay on plane to maximize fuel economy. Trying to find the happy middle ground what is your slowest planing speed. I believe I can plane at 2900 rpms but I think my stern is digging in a little at that speed.

Light load - 3700 RPMs & about 18/19 MPH

[Guest]

3700 RPMs just to stay on plane..you are only getting 18mph at 3700 rpms? What kind of boat do you have?

LazyCrusr wrote:
Light load - 3700 RPMs & about 18/19 MPH

[Guest]

I suppose I could go slower with trim tabs down to keep the stern up and bow level but doesnt tabs down also increase drag and thus, impact fuel economy?

waynepj3 wrote:
3700 RPMs just to stay on plane..you are only getting 18mph at 3700 rpms? What kind of boat do you have?

[Guest]

I find that the boat seems happiest around 3800 rpms. I can maintain plane at that speed with no tabs. With full tabs I think I can drop down to 3200.

[cwiert]

wfarr wrote:
I find that the boat seems happiest around 3800 rpms. I can maintain plane at that speed with no tabs. With full tabs I think I can drop down to 3200.

Yup. I concur with this. And at 3800 rpm, I'm doing about 28-31 mph...depending on current and gear on board. That's probably too fast for your wife. Just bring the rpms and the tabs down and you can stay on plane going slower (although probably not as fuel efficient).

[Guest]

waynepj3 wrote:
3700 RPMs just to stay on plane..you are only getting 18mph at 3700 rpms? What kind of boat do you have?

I mis-spoke, tried it tonite. In the boat by myself, not even a dog, and got more like 22 MPH, but yes I can only stay on plane down to maybe 3700, at 3600 it clearly has fallen off a bit. This is using trim tabs too.

My boat does not plane as well as most,,,,I think that I have the wrong prop. And of course, I have 2 of them

Boat info is in sig,,,,,a '95 2452, 4 blade aluminum Solas, 14.75x15 pitch - 5.0 Mercruiser

[Guest]

cwiert wrote:
Yup. I concur with this. And at 3800 rpm, I'm doing about 28-31 mph...depending on current and gear on board. That's probably too fast for your wife. Just bring the rpms and the tabs down and you can stay on plane going slower (although probably not as fuel efficient).

+1 it hits waves very nice at that speed also, I usually drive at cruise or slow (what im mostly at) around 7-8mph.

[Guest]

I like 3600-3800 RPMs on plane approx 30 MPH tabs up. Honestly I rarely go that fast, more hull speed. For speed, we have jet skis!

[JimMc]

I can plane down to about 3100 RPM using 1/4 tabs

I typically plane in the range of 3300 to 3800. That puts at about 25 to 28 MPH I think.

Or we cruise at hull speed at about 800 RPM.

[Guest]

I can't tell you the minimum because I'd never run there. It's simply awful to lug the engines like that. On top of the fuel you throw away, you're putting a lot of stress on the motors. Explain that to her. My own minimum is about 3500 when approaching the harbor, or similar situations.

And what's the issue with "going fast?" The 3055 is at comfortable plane and cruising at only 30-32...what's not to like about that? It it waves in bad weather, or what?

[RGrew176]

When I had my 3055 with 5.7's and stainless props my minimum planing RPM's were 3100. That gave me a speed between 26 to 28 MPH depending upon conditions. My boat did not have bottom paint and that could make a difference. This 3100 RPM was with no trim tabs engaged. I don't know if it helps but that was what worked for me. I also boated in fresh water not sure if salt water makes a difference.

[Guest]

SwampNut wrote:
On top of the fuel you throw away, you're putting a lot of stress on the motors.

If placing stress on the engines is a concern, you can always switch to lower pitched props. This will allow you to attain lower speeds in a manner that won't place excess stress upon your engines.

[Guest]

OOPS

I apologize guys, I just now realized the actual title of this thread.

Should not have posted here, sorry

[cwiert]

LazyCrusr wrote:
OOPS

I apologize guys, I just now realized the actual title of this thread.

Should not have posted here, sorry

Well, you do have the 305 engine. I could see the confusion. :hammer