What rpm do you all cruise at?

[f_inscreenname]

I run a small block V-8 in a 19’ boat . WOT is around 4700rpm’s and I can hold a high bow plain around 2400rpm’s. I end up cruising at around 3200 just trying to be nice to the motor but I have found a lot of people here running at 3500 to 3600rpm’s or higher. I have done a couple long runs at that rpm but always wondered if there was some sort of rule like “400 rpm extra after on a plain” or “ just before the 4 barrels kick in”. What do you guys go by or is it just a feel thing. Never worried about it before but I am taking longer and longer trips and the gas is killing me. I figure somewhere about mile and a half per gallon. If I cant cut down on the gas I will have to make shorter trips or tow it where I want to go but that wont help much with the bridge tolls for truck and trailer back and forth and gas for the truck.

 

[Ralph 123]

Re: What rpm do you all cruise at?

All depends on how fast I want to get where I'm going - I have a 28' Formula with twin 350s (5.7L) and typically cruise 2800 - 3200 RPMs which puts me around 35 - 40 MPH in salt water moderate chop.

 

[Dunaruna]

Re: What rpm do you all cruise at?

23ft glass deep 'V' with a 302w & 280VP. Same cruise RPM's as you, I use my flowscan to do minor adjustments for the 'sweet spot'.<br /><br />I've recently fitted a permatrim and now cruise on plane (nose level) at about 2900rpm.<br /><br />Aldo

 

[Boomyal]

Re: What rpm do you all cruise at?

Originally posted by Dunaruna:<br /> 23ft glass deep 'V' with a 302w & 280VP. Same cruise RPM's as you, I use my flowscan to do minor adjustments for the 'sweet spot'.<br /><br />I've recently fitted a permatrim and now cruise on plane (nose level) at about 2900rpm.<br /><br />Aldo

Dunaruna, what is a flowscan????

 

[ZmOz]

Re: What rpm do you all cruise at?

Originally posted by Boomyal:<br />Dunaruna, what is a flowscan????

http://www.iboats.com/mall/index.cgi?keywords=flowscan <br /><br />A fun toy, but it would take a LONG time to make up for the cost with the gas you save...

 

[Dunaruna]

Re: What rpm do you all cruise at?

I thought they were common. <br /><br /> http://www.iboats.com/mall/index.cgi?*******=436164545&keywords=flowscan&submit.x=48&submit.y=10 <br /><br />I've actually got the Navman version but it does exactly the same thing as the flowscan. Coupled to the GPS it gives me MPH or MPG (or knots & litres, knots & gallons, kilometres & litres etc.etc.) or it can be formatted to give gallons per minute (in my case litres per minute) or 10 minutes or whatever you want. Its a very accurate fuel usage computer.<br /><br />ZmOz, I was a good boy last year, Santa gave it to me <br /><br />Aldo

 

[qaztwo]

Re: What rpm do you all cruise at?

you guys are pretty fancy, I use a old fuel flow meter from a plane, can normally find them cheap on ebay, and use my hand held gps to find out my exact speed, or just use the speedo to give me a rough idea. Just my 2 cents.

 

[tommays]

Re: What rpm do you all cruise at?

with a 3.0 in a 19 ft and a 5 person 800 pound of crew 3800 rpm with a 15*19 gives about 24 mph<br /><br />with a 14*19 and 2 people i run about 3200 and go about 28 mph<br /><br />its funny with the 15*19 the load on the motor is so low the whole boat is so much smother and the gph is less than 4<br /><br /><br />tommays

 

[surfer23505]

Re: What rpm do you all cruise at?

It all depends on the size of boat. I have a 35' egg harbor with twin crusader 350's and if i want to run it not wide open, i run in the lower 3000's and do about 15 or so knots.

 

[surfer23505]

Re: What rpm do you all cruise at?

Then again i still need to do some tweeking on the engines to get more speed. just go a moderate amout depending on what your motor will do wide open and watch you temp and you should be fine.

 

[flashback]

Re: What rpm do you all cruise at?

21 ft scorpion cruises good at about 2300-2600 RPM. which equates to about 25-30 mph....

 

[qystan]

Re: What rpm do you all cruise at?

I run a 1991 Bayliner 24ft Trophy with Merc 5.7 Alpha 1, 15x19 prop. <br /><br />Best rpm is around 3500 giving 30mph.<br /><br />Navman 5500 says 60 litres/hr or 15 gal/hr. <br />0.49 miles/litre or 1.96 miles/gal.

 

[cobra 3.0]

Re: What rpm do you all cruise at?

I run 3200 rpm 16 ft bowrider 3.0 OMC Cobra at around 22 - 24 mph with a 14 x 17" prop anyhere from 3 to 6 people.

 

[neilmw]

Re: What rpm do you all cruise at?

1987 Sea Ray, 3.7lt merc 23" prop, 3000-3200, 3adults 2 kids 25mph, nice and comfy.

 

[Swishguy]

Re: What rpm do you all cruise at?

2004 Glastron mx 185 with 4.3 efi volvo penta outdrive & 23 pitch ballistic stainless prop. 3,000 rpm cruises nicely at about 35 mph.

 

[RatFish]

Re: What rpm do you all cruise at?

20' Bowrider, 5.0L (220HP) Mercruiser Alpha 1. I cruise in the 2800 RPM to 3200 RPM range.<br /><br />Take a look at Boattest.com. They give some performance info on their test rigs. Maybe yours is listed.

 

[snapperbait]

Re: What rpm do you all cruise at?

21' Openfish.. Heavy boat with a very deep v entry.. 302 ford efi, 1:1 gear, turning a 13x13 prop...<br /><br />I run it 2800-3200 and it seems happy to cruise there... 3000 rpm puts the speed right at 22 knots on the gps...<br /><br />In a usual 30-35 nautical mile round trip, it'll burn 15-16 gallons...