Cruise speed for ms350/390

[Cold Duck]

Just saw an ad for MS390 on Yachtworld showing MS390 specs: cruise 14kts, max 15kts. At first, I thought this as over optimistic Sales BS. But I really don't know how everyone drives their MS350/390s. I just have my data. I bought my 350 in Santa Barbara and cruised it to the Sacramento Delta, about 350nm. I cruised at 1800-2000 rpm with my Cat 3116, nice long runs with fill ups so I got good fuel burn data. Did about 8.5kts getting 2.1nm/gal. Now in the Sac Delta I use the vessel totally different, normally 15-30nm runs (mostly 15nm) and just put 100 gal of fuel in at a time so I don't get any performance data. But, with these short runs, I even throttle back to 1600 rpm doing 7-7.5 kts. In the delta, the ride is as much fun as getting to our destination. I never got the MS350 for speed, never been WOT. Sooooo..... I would like to see what other owners cruise their MS350/390s at realizing there is no correct or optimum answer here, just getting a feel how the boats are used by different people. Does anyone do 14kts and if so, where and why? Realize a lot of boats have a Yanmar and many different hp combos but we should get a feeling for what feels best to everyone, single and twin engines, and how they use the boat. I know there's a lot of expert opinions on boat speeds and efficiency, but I would like to keep this to the MS350/390 only so we can compare apples to apples. So lets hear from you guys.

 

[rslifkin]

Depending on how that one is powered, they're either full of crap or they're quoting speed with the engine(s) at max continuous (which would be the maximum sustainable cruising speed). A quoted cruising speed in an ad like that probably has no relevance to how anyone would operate the boat in the real world.

 

[Gdavid]

Just saw an ad for MS390 on Yachtworld showing MS390 specs: cruise 14kts, max 15kts. At first, I thought this as over optimistic Sales BS. But I really don't know how everyone drives their MS350/390s. I just have my data. I bought my 350 in Santa Barbara and cruised it to the Sacramento Delta, about 350nm. I cruised at 1800-2000 rpm with my Cat 3116, nice long runs with fill ups so I got good fuel burn data. Did about 8.5kts getting 2.1nm/gal. Now in the Sac Delta I use the vessel totally different, normally 15-30nm runs (mostly 15nm) and just put 100 gal of fuel in at a time so I don't get any performance data. But, with these short runs, I even throttle back to 1600 rpm doing 7-7.5 kts. In the delta, the ride is as much fun as getting to our destination. I never got the MS350 for speed, never been WOT. Sooooo..... I would like to see what other owners cruise their MS350/390s at realizing there is no correct or optimum answer here, just getting a feel how the boats are used by different people. Does anyone do 14kts and if so, where and why? Realize a lot of boats have a Yanmar and many different hp combos but we should get a feeling for what feels best to everyone, single and twin engines, and how they use the boat. I know there's a lot of expert opinions on boat speeds and efficiency, but I would like to keep this to the MS350/390 only so we can compare apples to apples. So lets hear from you guys.

Your numbers line up with my parents' 390 with a Yanmar 370. It will run 14-15 knots at full throttle but, it is unpleasantly loud, the wake is about 2.5' and it just isn't enjoyable. We run it up to ~3000 rpm near the end of a long run to blow out the soot but the boat spends most of its life at 1600-1800 rpms. This yields about 7.5 knots.

 

[Phyrcooler]

2001 - 390

Mine was equipped with twin Yanmar 4LHA-STE 240 hp. I could cruise at 7 knots getting 2.5 - 3 kmpg. My long distance, off-shore comfortable cruising was 2700 - 2750 rpm making about 11.5 - 12 kt. This kept rolling to a minimum, and was enjoyable. Sound levels were acceptable on the flybridge. Full throttle was around 3300 - and depending on sea state, I was running 15 - 17 kt. My fastest was 18kt on flat water/zero wind… and a freshly painted bottom. I almost never ran from below, as the view from above was unbeatable. And the noise in the cabin at anything above idle was brutal.

 

[J.T kearney]

MS 390 speed

I have a 98 350 with a single yanmar 6LYA-UTE (315 hp) that I cruise at 2000 RPM normally and burning about 3.75 gal per hour. that will push me at 8 + knots. not real bad in the noise department at the lower helm but awesome on the fly bridge. I try to rev up the RPMs to full throttle every couple of hours to clear out any carbon build up.
Cheers J.T.

 

[johnma]

i run my 2003 390 w/ single Yanmar 370 at 1800 rpms. gives me about 8.5 kts. If i'm by myself with tanks low I might get 14 kts flat out but doing it would just be silly and woult trash the engine in no time. it's not a planning boat

 

[Diverrob]

I have a 2007 34 Trawler with a single Yanmar (315hp) and cruse at 2300 rpm which gets me 7kts and burns 2.5 Gallons/hour. WOT gets me about 10kts, but that’s burning a lot of fuel and is loud.

 

[jleonard]

ust saw an ad for MS390 on Yachtworld showing MS390 specs: cruise 14kts, max 15kts. At first, I thought this as over optimistic Sales BS

That's exactly what it is. Mainship published those numbers to compete i the marketplace. With a new empty boat those numbers are achievable, but not for the long haul.
That's one of the reasons they didn't put a keel and big rudder on them, so they could get the advertised speed on record.

 

[Cold Duck]

Thanks guys for all the great inputs. I guess I am going to have to do a WOT run. Tuff cause I am almost always towing something, anything from a mini Fish sail boat to our 26' daycrusier. Like to tow the daycruiser out to an Island we belong to then boat to B'fast or dinners in the daycruiser. Lots of great restaurants on the water in the Delta. Towing we usually just run at 1600rpm with the Cat 3116 still getting 6-7kts depending on tidal currents.

 

[Shrew]

I have a 2007 34 Trawler with a single Yanmar (315hp) and cruse at 2300 rpm which gets me 7kts and burns 2.5 Gallons/hour. WOT gets me about 10kts, but that’s burning a lot of fuel and is loud.

This is inline with our single Yanmar 6LPA-STP2 (315hp). We run at 2,400rpm. Tide takes a large roll in SoG. Depending on tide 6.5kts - 10ts. In flat water with a slack tide, I'd say about 8.5kts @ 2,400.

The Mainship numbers for the original Cat 3116 seemed much faster for slower RPM's.

 

[Cold Duck]

The Mainship numbers for the original Cat 3116 seemed much faster for slower RPM's.

It's very difficult to compare different engines/trans/prop/hull configurations. I had a 45ft trawler with 2 400hp Detroit V8s that loved to cruise 10kts @3000 rpm. Not now in Ca so I can't look at the exact reduction on the tranny and I believe I have a stock (for Mainship install) prop. Only owned for a few years and never gone over 2000 rpm. I have never been one to run WOT in any of my boat engines (unless racing but that's a different story). Since I am mostly towing there's no need to kick up the power. I have not been down bay to SF enough to get a read on higher rpm performance. Maybe this next summer I can make a long run at 2000 rpm for better numbers. And yes, we have significant tidal and river currents that have to be figured in. We can add 2 kts due to currents, nice when with you, bummer going against.

 

[Shrew]

This is inline with our single Yanmar 6LPA-STP2 (315hp). We run at 2,400rpm. Tide takes a large roll in SoG. Depending on tide 6.5kts - 10ts. In flat water with a slack tide, I'd say about 8.5kts @ 2,400.

The Mainship numbers for the original Cat 3116 seemed much faster for slower RPM's.

It's very difficult to compare different engines/trans/prop/hull configurations.

In this case we're talking the same trans, same prop, same hull.

 

[Hawkshaw1]

We have a 390 with a single CAT 3126. We cruise at 9 knots at 17-1800 rpms. WOT is uncomfortable, throws a big wake, and is pretty loud. Top speed is about 13 knots, but I know it's not worth the fuel being burned.

Hawk

 

[Pete Meisinger]

Sure it is obtainable with the right load and engine combination but... I wish manufacturers and agents would be more honest or at least more realistic. Like maybe include fuel burn numbers at that speed.

pete

 

[Cold Duck]

Sure it is obtainable with the right load and engine combination but... I wish manufacturers and agents would be more honest or at least more realistic. Like maybe include fuel burn numbers at that speed.

pete

Yup, as soon as you put anything aboard that makes the boat liveable those numbers go out the window. Most trawlers realistically live at 10kts and below. Obviously we didn't get these boats for speed

 

[jclays]

That's exactly what it is. Mainship published those numbers to compete i the marketplace. With a new empty boat those numbers are achievable, but not for the long haul.
That's one of the reasons they didn't put a keel and big rudder on them, so they could get the advertised speed on record.

They do have a keel.

 

[jclays]

I have a 97/350 with twin Volvo TAMD41 P-A turbos.
Cruise between 2000RPM 9kts to 2500RPM 10.5kts. WOT is 3750 I get 16.5 to 17kts depending on sea conditions. Pretty close to the Mainship specs. I dont load her with too much stuff.