To plane or just cruise

[HUMPH]

My 320DA had 2 speeds, idle and on full plane. My diesel 410DA spends a lot of time at about 8knots or less just enjoying the trip. I also spend a lot of time between 2250 and 2400RPM.

 

[quality time]

I am the total opposite of you guys. The only poking around i do is out of the harbor at 900 rpm since the channel is no wake. 3350 the rest of the time. These boats are called "Sport Cruisers" and not trawlers for a reason.

I'm with Alex. Spool 'em up if you got 'em!

 

[2000SR380]

One item I did not see covered here is Blower Motor operation. When we run at lower speeds we also run engine room blowers because you loose most of the airflow from the side vents. This is less important in fuel injected boats, but better safe than sorry right? Engines do like to be run. Nothing wrong with cruising at cocktail speed and enjoying the ride, but be sure to spool the engines up for 5 or 10 Minutes before you make the channel going back to your marina. Just like taking your car on the freeway now and then. When all it does is run around town, and do grocery trips, the engine builds up sludge, and carbon deposits. It helps to do regular maintenance, but if you do not run your car up to speed, now and then, it will develop more problems and die sooner. Same with your boat. If you are puttering around to save money, you will spend more in maintenance than you save in fuel, and you do not have the optimum hull design characteristics. Get a Simi-displacement boat and call it a day. 'Hull-Speed' is the speed you can go BEFORE the boat tries to plane. If you stay a tick below 'Hull-Speed', you will find your best 'Trawler/cocktail-run' economy. From the point your boat starts trying to plane, you will get abysmal economy until it achieves plane. Our 380DA likes 1500-1600rpm for 7-8kts, and 3300-3500rpm for most efficient plane. We typically run on plane and slow down for scenic area's, whales, dolphins, etc. We do like to slow cruise the San Francisco water front, and the Sausalito channel. Angel Island, and the Alameda channel have some scenic area's that are fun to take in at slow speeds. I am not saying get carried away with going everywhere like your hair is on fire. I am saying express cruisers are built to run at speed, and that is their first best purpose.

 

[billnpat]

One item I did not see covered here is Blower Motor operation. When we run at lower speeds we also run engine room blowers because you loose most of the airflow from the side vents. This is less important in fuel injected boats, but better safe than sorry right? Engines do like to be run. Nothing wrong with cruising at cocktail speed and enjoying the ride, but be sure to spool the engines up for 5 or 10 Minutes before you make the channel going back to your marina. Just like taking your car on the freeway now and then. When all it does is run around town, and do grocery trips, the engine builds up sludge, and carbon deposits. It helps to do regular maintenance, but if you do not run your car up to speed, now and then, it will develop more problems and die sooner. Same with your boat. If you are puttering around to save money, you will spend more in maintenance than you save in fuel, and you do not have the optimum hull design characteristics. Get a Simi-displacement boat and call it a day. 'Hull-Speed' is the speed you can go BEFORE the boat tries to plane. If you stay a tick below 'Hull-Speed', you will find your best 'Trawler/cocktail-run' economy. From the point your boat starts trying to plane, you will get abysmal economy until it achieves plane. Our 380DA likes 1500-1600rpm for 7-8kts, and 3300-3500rpm for most efficient plane. We typically run on plane and slow down for scenic area's, whales, dolphins, etc. We do like to slow cruise the San Francisco water front, and the Sausalito channel. Angel Island, and the Alameda channel have some scenic area's that are fun to take in at slow speeds. I am not saying get carried away with going everywhere like your hair is on fire. I am saying express cruisers are built to run at speed, and that is their first best purpose.

Well said….but for me its not all about saving fuel. YES, blower operation is vital at slow…...agree ….On plane is fine to a point, but then with the noise, and bouncing around, and if you happen to have any guests aboard , speaking to them is impossible, When I'm alone i plane 2/3rds of the time…the boat is lighter and more frisky and i can really fly, but with guest aboard it's i would say
NOT very enjoyable to be planning continuously… Thats what I'm talking about….The ride i would think is more enjoyable slower and taken in the scenery etc,, not spilling drinks, and not being able to converse to your guests…. Drive by your self ??? open her up…….

 

[searay40dad]

I still get a little thrill every time the turbos spool up. When they kick in, it throws you backwards if you're standing up which is pretty cool feeling. it's almost as good as sex. I didn't buy a boat with these motors to poke around. I like to rock and roll. Nothing like seeing a canbote under power trying to take my wake. I also try to always run WOT for a short period every time I'm out just to make sure everything is operating to spec, i.e. temps, pressures, rpms, engine load, speed. I do the same with the gen--load it and run it.

 

[billnpat]

Quote:

I also try to always run WOT for a short period every time I'm out just to make sure everything is operating to spec, i.e. temps, pressures, rpms, engine load, speed. I do the same with the gen--load it and run it.
DITTO :thumbsup:, short period of time is what I'm talking about…..YES….​

​

 

[k9medic]

Quote:

I also try to always run WOT for a short period every time I'm out just to make sure everything is operating to spec, i.e. temps, pressures, rpms, engine load, speed. I do the same with the gen--load it and run it.
DITTO :thumbsup:, short period of time is what I'm talking about…..YES….​

​

This is my MO as well. Relax at around 8kts burning 3.5 gph but at least once a trip WOT to see what she'll get.

 

[NorCal Boater]

Aaahhh....planing speed. I vaguely remember that. I don't get that thrown back feeling when the turbos spool up and I miss it. Bill, if you are doing your slow cruise at 2000 RPMs you probably get a lot of stuff thrown at you by the people that endure that wake. Slow the boat down a bit more and make everyon's life a bit happier.

My solution to the slow speed cruising? I bought a 23' boat that goes faster. Best of both worlds.

 

[billnpat]

Aaahhh....planing speed. I vaguely remember that. I don't get that thrown back feeling when the turbos spool up and I miss it. Bill, if you are doing your slow cruise at 2000 RPMs you probably get a lot of stuff thrown at you by the people that endure that wake. Slow the boat down a bit more and make everyon's life a bit happier.

My solution to the slow speed cruising? I bought a 23' boat that goes faster. Best of both worlds.

That slow cruise you say is NOT in a wake zone but out deep in the water, and 2000 RPM is not really a significant wake maker….

 

[WDCboater]

yep....1600-1800=cocktail speed........anything close to 2000 I'm just pushing water and burning fuel.....3200-3400 cruise gives me right at 30mph.

This is about the same with my boat.
Anywhere under 1800 is a comfortable ride. Once you get above that and don't get up on plane you're putting stress on the engines. (This is what the techs at my dealer have told me) we cruise comfortably at 3200-3500.

We do several 50-60mi cruises a season and unless you want to spend all day getting somewhere we tend to get up on plane and cruise around 26-29mph. With that said, I like the idea of a boat that cruises at 10-12knts and can cruise over 500mi on a single tank.

 

[Woody]

I think the big factor in plane or putt is ‘where do you boat’ and ‘where are you going’. Are you just going for a ride? I’m on plane almost all the time, sure I might slow to check something out, take a picture, or get another quart of beer from the cooler, but then it’s back on plane.

We don’t ’go for a ride’, we put effort into trying to go on a trip w/overnights each time we leave the dock. We like to go places and we’re running on plane the majority of the time.

 

[KC_Sundancer]

I think the big factor in plane or putt is ‘where do you boat’ and ‘where are you going’. Are you just going for a ride? I’m on plane almost all the time, sure I might slow to check something out, take a picture, or get another quart of beer from the cooler, but then it’s back on plane.

We don’t ’go for a ride’, we put effort into trying to go on a trip w/overnights each time we leave the dock. We like to go places and we’re running on plane the majority of the time.

That's pretty much how we run too with destinations in mind. When giving friends National Lakeshore tours, once out there, it's usually more on the cruise side, taking in the scenery, photos etc...
It's needles to worry about what's harder on the drive train, they can take way more abuse than your giving it either way. As long as your keeping up the maintenance you'll never see a difference.
I say get out there and run whichever way you like.

 

[src]

Talking about specific RPM's is pretty useless unless you have the same boat/engine configuration. In general, anything above hull speed but below planing speed is just throwing fuel away. Basically, once your boat starts changing attitude (pitching up), you are transitioning from displacement cruising towards planing. At that point, you are probably in the least efficient mode, as you are now constantly trying to push the boat up your bow wake and "out of the hole".

Going back to RPMs, for my boat (310DA w/twin 7.4's), I hit that point around 1350 RPM. From there, I know that until get the boat on plane (around 2800-3000 RPM), I am just burning buckets of fuel for not much speed increase. I could run at 2500 RPM doing about 15 MPH with the boat's nose pointing at the sky, but if I bump up to 2800 to get on plane now I'm sitting at around 24 MPH. For me, there is just no value in running faster than hull speed but slower than planing.

 

[Searaybio270]

I am not sure what speed I should be when we are out. I prefer to go about 8 to 10 knots/miles per as it is comfortable, I can talk and listen to the music. I also take her up to 3200 and run about 22 to 24 MPH's when going across the bay or sometimes up the river. WOT once in a while but I do understand the need to do that. Now if I could only get the Admiral to show up on time we could take our time going to our destination. One day - Maybe!!

 

[2000SR380]

Going back to RPMs, for my boat (310DA w/twin 7.4's), I hit that point around 1350 RPM. From there, I know that until get the boat on plane (around 2800-3000 RPM), I am just burning buckets of fuel for not much speed increase. I could run at 2500 RPM doing about 15 MPH with the boat's nose pointing at the sky, but if I bump up to 2800 to get on plane now I'm sitting at around 24 MPH. For me, there is just no value in running faster than hull speed but slower than planing.

On a recent trip from Pillar Point home we encountered about a 5knt ebb approaching the Golden Gate (There was a 5-10ft swell running and we launched off a pretty good wave early in the trip, Almost achieved low orbit, spilled the coffee, rearranged the cabin, so we had slowed down to 'trawler speed' messing up my timing). When we turned in at the bar, heading toward the gate, the following see was directly astern and we were fighting the ebb. This set up a situation (steep waves astern with opposing current) that made the boat feel very unstable at the 7-8 knot RPM. As the stern lifted the small rudders did not have much effect and the boat tried to broach (requiring a lot of steering input). Planning speeds would have broken stuff. I found that if I adjusted the RPM to our 15-16 knot RPM, we were back to 7-8 knots over the bottom, which allowed us to move just slower than the swell. So for a short time we suffered the "in-between" fuel economy, in favor of a more stable comfortable ride. I have some cool video of our 380DA running down wind off shore on plane in 5-7 foot swell. You can her the RPM change as the boat climbs the waves and drops off, constantly working between plane and just off plane, but the ride was great and the autopilot was driving! [video=youtube;JodKD8JyXjs]https://www.youtube.com/watch?v=JodKD8JyXjs[/video] https://www.youtube.com/watch?v=KnVx50QXMqU Beyond compensating for sea state in rough conditions I am in agreement. Below hull speed or move to planning speed. No reason to run in between. burns a staggering amount of fuel.

 

[1990-270-da-lover]

We run at hull speed most all the time, somewhere between 1200 and 1700 rpm. Depending on wind speed and tidal flow we can expect about 8-10 mph, which is fine sine we are towing our 8'6" dinghy. As others have said being able to converse with the guests and not spill drinks all over the cockpit is a big plus for us. As far as fuel consumption goes we burn somewhere I the range of 6-8 gph.

 

[Billfletcher]

On a recent trip from Pillar Point home we encountered about a 5knt ebb approaching the Golden Gate (There was a 5-10ft swell running and we launched off a pretty good wave early in the trip, Almost achieved low orbit, spilled the coffee, rearranged the cabin, so we had slowed down to 'trawler speed' messing up my timing).

Coming through the GG is quite an experience, and not for the inexperienced. In the mid 80's I went through on a ship in the winter, with massive swells/wind. One barge had hit the rocks, and we had a CG escort after waiting outside for many hours to enter. I like the approach you describe.

 

[JVM225]

I'm not a big fan of planing, although i do it to get the boat juices flowing, but not for long,
i like to just ride out at 2000 RPMs and enjoy the water without speeding to nowhere fast...

I hear that going at low 2000 RPMs uses a lot of gas and stress on the engines....
that so??:huh:

Am i alone here.???

I kind of like to just cruise around slowly when I have the time, and there is no traffic out there.
At 2000 RPM I am wasting a lot of gas just pushing water, and not getting up on plane. I find that 1200 RPM is a nice slow cruise speed for my boat. The bow is down, cutting nicely through the water, and engines are nice and quiet.
If you don't have them already, some sort of flow gauges are a good investment. Conditions can vary greatly with wind, chop, and current. Each situation has a sweet spot when it comes to max fuel efficiency. The fuel flow gauges really come in handy to find that sweet spot.

 

[billnpat]

i kind of like to just cruise around slowly when i have the time, and there is no traffic out there.
At 2000 rpm i am wasting a lot of gas just pushing water, and not getting up on plane. I find that 1200 rpm is a nice slow cruise speed for my boat. The bow is down, cutting nicely through the water, and engines are nice and quiet.
If you don't have them already, some sort of flow gauges are a good investment. Conditions can vary greatly with wind, chop, and current. Each situation has a sweet spot when it comes to max fuel efficiency. The fuel flow gauges really come in handy to find that sweet spot.

perfect :thumbsup::thumbsup:

 

[moparlvr4406]

we run the 340 12-1500 for coctail speed and she will stay on step at 2800 with a touch of tab
guess it depends on how fast you need to be somehere