Good running speed, opening her up

[Newbie]

I have always subscribed to the school of "engines need to be revved every so often to remain in good tune".
Every car I drive gets redlined once or twice a day and I run our 340 at WOT twice a year for about 5 minutes when we make back from our favorite cove.

I also believe that an ample warm up period ... about a mile for me ... is important before running up on plane and I also make sure to run the boat at 1200 rpm for about 15 minutes after coming off plane to cool things down.

Just look out for me in my little 230BR on the lake when you do it :grin: Theres not many areas of the lake to run 40mph for 5 min straightline. I am thinking of moving my 340 to the lake for the summer months next year though so I'll have to do it too.
I tached mine out a few weeks ago at a tad over 4400 coming home from a long trip, full load, full fuel etc. Damn motors sound like they are about to come apart but it sure feels good! My normal cruise is at 3450, a good balance between feeling good and fuel burn. SB

 

[Alex D]

Just look out for me in my little 230BR on the lake when you do it :grin: Theres not many areas of the lake to run 40mph for 5 min straightline. I am thinking of moving my 340 to the lake for the summer months next year though so I'll have to do it too.
I tached mine out a few weeks ago at a tad over 4400 coming home from a long trip, full load, full fuel etc. Damn motors sound like they are about to come apart but it sure feels good! My normal cruise is at 3450, a good balance between feeling good and fuel burn. SB

Hi Newbie ... we have been on the lake for 5 seasons and from our slip to some of our favorite coves by the dam is a 12 mile run and i think there is plenty of space to open her up. Of course not during the main season on weekends but we always, always run at 3400 to 3600 rpm with a crusing speed around 28 to 30 mph. WOT on our 340 is 4600 rpm running 40.5 mph SOG on the GPS.
Let us know if you move the 340DA up to the lake. BTW SMYC has covered wet slips available and we love that marina. It is the best boat Sea Ray shop far and wide too!

 

[Newbie]

Alex, if you don't mind me asking, what are the slip rates there? I am thinking of running twin 30 or single 50 amp service to the end of my dock but its nearly a 200 foot run from the house. Just the wire alone would be a fortune. I can't decide on whether or not to do it since I'm not sure we would bring the 340 up every summer, just give it a trial run next summer. Thanks Steven Brown

 

[Alex D]

PM on its way

 

[hack4alivin]

Bill

Theoretically, the lower the RPM you turn thru-out the engines life span, the longer your motors will last. But you also have fuel economy to consider, planing speed to consider, your desire to get somewhere fast, and then there's the "sweet spot" when your boat feels it's running best. So how do you sort all this out? :smt101:smt101:smt101

The "sweet spot" on my single 350 MAG powered 260DA is 4000 RPM just like it is your 320DA. But I don't run at 4000 RPM because my fuel flow is most effecient at 3800 RPM. So instead I choose that RPM as my cruising speed most of the time because the boat is still nicely on plane and is only running about 2 mph slower than it does at 4000 RPM. So I feel I am helping out the longetivity of my engine as well as saving a few dollars on gasoline. But that doesn't mean that I don't ever run faster than that. If I am in a hurry I'll run at 4000 RPM and I'll open her up and run her at maximum RPM for a few minutes occasionally as well. For me at least, the trick is not to run above 4000 RPM for any exended period of time.


Dave

According to my Smartcraft there is not much of a fuel consumption difference between running 3800 verses 4000. Now last year when I had the 280 with the single 496, when I opened her up the gas needle was going down as fast as the RPM’s were coming up. Generally unless I am going on a long cruise I am not running my speed for the best gas mileage though. I figure it is what is it is.

This whole thread started because I read someone’s post that said running 4000 RPMs consistently would do premature damage to your engines. I started thinking that my boat just seems to be real comfortable in that range.

I did have some fun the other day though. When returning home from the Chesapeake Bay into the Gunpowder River you follow the channel markers in the bay and make a hard turn to port around Green 7 into the Gunpowder. So as we were coming to the marker I told my wife to “hang on” as I turned her hard around it I throttled up at the same time. The boat just stuck that turn like a Nascar on a high bank turn. Too cool! :thumbsup: It reminded me of my Motocross years of slamming around corners in the berms.

 

[mrsrobinson]

So, do folks gradually put their boat up on plane, or like Hack4livin push full throttle then start backing off? Most of the time I push full throttle then gradually back off to crusing RPMs, 3300 - 3400, but only after the engines have warmed up. Sometimes I will go from idle, to 1200 RPMs for a few minutes, then to 1500 RPMs for a few minutes then to full throttle, then back to cruising RPMs.

 

[Alex D]

So, do folks gradually put their boat up on plane, or like Hack4livin push full throttle then start backing off? Most of the time I push full throttle then gradually back off to crusing RPMs, 3300 - 3400, but only after the engines have warmed up. Sometimes I will go from idle, to 1200 RPMs for a few minutes, then to 1500 RPMs for a few minutes then to full throttle, then back to cruising RPMs.

I don't firewall the throttles. Depending on load I need 60% to 75% throttle and I use "6 seconds" of tabs and she'll plane in about 8 seconds.

Once I had her loaded full with 10 people water and stuff once. At that time I firewalled the throttles in order to just get her up without hanging on the hump for too long. She still would have planed with 80% throttel but it would probably have taken 15 seconds or so.

 

[Vince_nj1]

I follow the same routine as you.. I pick up the RPM's to around 1800 for few seconds then nail it, then back down once I'm on plane.

 

[mrsrobinson]

"I use "6 seconds" of tabs"

I rarely touch our trim tabs. I leave the all the way bow down 95%+ of the time, especially when getting up on plane. I may adjust one of them if the boat is listing while on plane, but other than that I leave them full bow down.

I am curious what you do w/your trim tabs when getting up on plane and then once one plane.

 

[billandamy]

So, do folks gradually put their boat up on plane, or like Hack4livin push full throttle then start backing off? Most of the time I push full throttle then gradually back off to crusing RPMs, 3300 - 3400, but only after the engines have warmed up. Sometimes I will go from idle, to 1200 RPMs for a few minutes, then to 1500 RPMs for a few minutes then to full throttle, then back to cruising RPMs.

Personally, run and gun for me.

It's a frikkin machine, boys. A toy to play with. Rev her up, blast her open and frikkin go. You guys treat these things like china.

The fact is, they are MEANT to be driven, sometimes hard for a while. An engine wants to be in the high rpm's sometimes to get everything going. I relate it to your body....when you exercise, do you back off for fear of a heart attack or push it? I dont go to play hockey and say "oh tonight Im going to skate at 60% so I dont pull a muscle."

A client of mine is Marren Injection, a well known engine guy around here. We were speaking of his race cars and engines in general, and he says people baby motors far to much, and allow build ups by cruising all of the time on the highway doing 65. I have always thought this way from many motorheads telling me this, and it makes sense.

So stop being such frikkin dorks and blast around once in a while.

 

[Vince_nj1]

Most of my prior boating experience was with a 26ft sundancer and a 30ft sundancer. Both had stern drives. I used the trim tabs on both of those boats to get on plane. They came out of the hole a lot easier with tabs down. Once on plane I would back off the tabs and trim the drives.

My 320 has V-drives. I expected the same experience, but I found that the boat gets on plane without any problems without using the trim tabs. To be fair, I havent had a full load of people on board, but I did have full fuel and water tanks and one other 250 lbs person on boar and the boat got on plane without even breathing hard. (6.2liter engines).

Once on plane, I run the engines in the 3800 to 4000 range and dont use the tabs. That RPM levels the boat out nice. I was experminenting with lower RPMs and using the tabs, but I decided to just go a little faster. This chart from Power and Motoryacht is dead on with what I experience with my boat.. Notice the trim angle goes from 6.0 degrees down to 4.5 at 4000 RPMs and the fuel mileage increases.

http://www.powerandmotoryacht.com/boat-tests/sea-ray/1002searay320/index2.aspx

 

[hack4alivin]

Personally, run and gun for me.

It's a frikkin machine, boys. A toy to play with. Rev her up, blast her open and frikkin go. You guys treat these things like china.

The fact is, they are MEANT to be driven, sometimes hard for a while. An engine wants to be in the high rpm's sometimes to get everything going. I relate it to your body....when you exercise, do you back off for fear of a heart attack or push it? I dont go to play hockey and say "oh tonight Im going to skate at 60% so I dont pull a muscle."

A client of mine is Marren Injection, a well known engine guy around here. We were speaking of his race cars and engines in general, and he says people baby motors far to much, and allow build ups by cruising all of the time on the highway doing 65. I have always thought this way from many motorheads telling me this, and it makes sense.

So stop being such frikkin dorks and blast around once in a while.

Yea, I like that attitude. Ride her hard and put away wet. Rock and Roll:thumbsup:

 

[Alex D]

"I use "6 seconds" of tabs"

I rarely touch our trim tabs. I leave the all the way bow down 95%+ of the time, especially when getting up on plane. I may adjust one of them if the boat is listing while on plane, but other than that I leave them full bow down.

I am curious what you do w/your trim tabs when getting up on plane and then once one plane.

Greg .. if you do not touch your tabs that would be "bow up" feature because the more you apply tabs, the more "bow down" you apply.

By careful watching the speed and RPMs I now know that a certain amount of tabs will give the boat optimum efficiency (read max. speed at any given rpm). From my min. reasonable planing speed at 3000 rpm to no tabs needed at all in order to run max efficient (which is at 3700 -3800 rpm and up at about 30+ miles per hour) I need increasingly less tabs to achieve max speeds and efficiency as I transition through the rpm range. If I would not apply any tabs at 3400 rpm I would run less efficient with the stern dug in more pushing more of a bow wave than I can achieve with some tabs, which I measure by the relationship of the bow rail to the horizon. I have figured out over time at what attitude the boat runs most efficient and adjust the tabs accordingly

After I get on plane I usually pull the tabs back until my hull attitude is where the boat uns the fastest at a set rpm.

Using no tabs is less efficient than using tabs until I reach about 3800 rpm from where no tabs are needed and applying tabs would only create drag. using some tabs also makes planing so much easier without much bow rise and drama. She just kind of slips up on the hump and very fast too.

 

[Stray Cat]

I remember the days when a 350 Chevy redlined at 4000 rpm...now we are supposed to run em like we stole it? Bend a push rod or lose a lifter and see what pile of scrap you will have in the bilge....I've been to events where they take a car and raffle off how long before it blows up, only to see the engine run out of gas first. Then again it is not under much (any) load. I'm not opposed to hammering it for a short period, but the standard engines in the bilge were not built by a NASCAR builder by any means to endure routine max rpm for long durations....although Mercrusider likely would like us to.
my .02

 

[Geurk]

Personally, run and gun for me.

It's a frikkin machine, boys. A toy to play with. Rev her up, blast her open and frikkin go. You guys treat these things like china.

The fact is, they are MEANT to be driven, sometimes hard for a while. An engine wants to be in the high rpm's sometimes to get everything going. I relate it to your body....when you exercise, do you back off for fear of a heart attack or push it? I dont go to play hockey and say "oh tonight Im going to skate at 60% so I dont pull a muscle."

A client of mine is Marren Injection, a well known engine guy around here. We were speaking of his race cars and engines in general, and he says people baby motors far to much, and allow build ups by cruising all of the time on the highway doing 65. I have always thought this way from many motorheads telling me this, and it makes sense.

So stop being such frikkin dorks and blast around once in a while.

I agree with Billandamy. I bought a sport boat, not a cruiser. I run WOT a *lot*. I also have a jet ski, and I'm WOT most of the time on that as well. All scheduled maintenance is performed at all regular intervals.

Kind of like buying a Porsche and driving around like its Sunday all the time. These things are meant to bring smiles to our faces, and WOT does just that to me.

 

[mrsrobinson]

Greg .. if you do not touch your tabs that would be "bow up" feature because the more you apply tabs, the more "bow down" you apply.

By careful watching the speed and RPMs I now know that a certain amount of tabs will give the boat optimum efficiency (read max. speed at any given rpm). From my min. reasonable planing speed at 3000 rpm to no tabs needed at all in order to run max efficient (which is at 3700 -3800 rpm and up at about 30+ miles per hour) I need increasingly less tabs to achieve max speeds and efficiency as I transition through the rpm range. If I would not apply any tabs at 3400 rpm I would run less efficient with the stern dug in more pushing more of a bow wave than I can achieve with some tabs, which I measure by the relationship of the bow rail to the horizon. I have figured out over time at what attitude the boat runs most efficient and adjust the tabs accordingly

After I get on plane I usually pull the tabs back until my hull attitude is where the boat uns the fastest at a set rpm.

Using no tabs is less efficient than using tabs until I reach about 3800 rpm from where no tabs are needed and applying tabs would only create drag. using some tabs also makes planing so much easier without much bow rise and drama. She just kind of slips up on the hump and very fast too.

I leave them bow down all the time, unless she is listing and needs to be leveled out. I have moved them towards bow up while on plane and, she always goes up and the rpms/speed goes down, so I leave them full bow down, even when getting up on plane.

Should I be doing something different?

 

[techmitch]

something sounds strange there gregg, like alex said. bow down means to put the tabs down to force the bow down. normal (at rest position) of the tabs is all of the way up, hence - bow up...

 

[Alex D]

Yep techmitch ... "bow down" setting of the tabs means the tabs are fully extended. I wonder if Greg really means that he is driving around with the tabs fully deployed all the time. I have a hard time believing that. I think he means that he rarely or never deploys the tabs which would actually translate to be the full "bow up" position where the tabs are fully retracted.

My point is tabs are a valuable tool to speed up planing and run the baot at highest efficiency. So I use them all the time in as small measures as appropriate for the condition. Kinda like a pilot using flaps to manage slow speed lift.

 

[tobnpr]

I remember the days when a 350 Chevy redlined at 4000 rpm...now we are supposed to run em like we stole it? Bend a push rod or lose a lifter and see what pile of scrap you will have in the bilge....I've been to events where they take a car and raffle off how long before it blows up, only to see the engine run out of gas first. Then again it is not under much (any) load. I'm not opposed to hammering it for a short period, but the standard engines in the bilge were not built by a NASCAR builder by any means to endure routine max rpm for long durations....although Mercrusider likely would like us to.
my .02

I agree. There's no way to compare an engine run in an automobile to one run in a boat.
I don't think an automobile engine would last too long with your foot to the floor pulling a 5000 lb trailer up a steep incline every time you took it out.
Some people fail to remember that automobile engines "loaf" for most of their lives.

 

[Alex D]

I agree. There's no way to compare an engine run in an automobile to one run in a boat.
I don't think an automobile engine would last too long with your foot to the floor pulling a 5000 lb trailer up a steep incline every time you took it out.
Some people fail to remember that automobile engines "loaf" for most of their lives.

Not so sure about that .... regular car engines do last well in light truck aplications pulling trailers anywhere up to 9000 pounds on a regular basis. In these conditions it is the transmissions that give the trouble, not the engines. The 8.1/496 GM BB in my boat for instance is rated to tow 12000 lbs. and more in GM HD trucks and does this very well and for tens of thousands of miles when I look at all the smaller and larger construction companies around here and the huge trailers they pul daily with these trucks.
IF I then look at my computer in my car. OVer the last year my overall average speed is 35 miles per hour, yes that's it including longer trips and the daily commute to work. This would mean that 100 hours for car/truck engine equate to 3500 miles. So my engines in my boat have 350 hours, that's like 8750 miles of "heavy towing". Hardly a challenge ... the guy who built our house had two GMC 3500 trucks with 8.1 / 496 engines that had over 100,000 miles on them and he tows 10,000 pound trailers 75% of the miles driven with these trucks.

SO while you might say car engines loaf a lot ... light duty and medium duty truck gas engines, like the ones marinized in our boats, do last while theya re working hard for most of their life.