38E speed question

[Helmsman]

For those of you that own a Helmsman 38E, what engine do you have installed, and what is the top speed you have experienced? I am interested in top speed experienced. If Scott or others see this, would like their input also. Thanks for any input.

 

[N4061]

Speed

We installed the Cummins 6.7 380hp Diesel engine (love that engine) and would cruise between 7.0 - 7.5 knots. WOT was about 9.5 knots while burning more fuel than you want to know. Did that occasionally just for the engine itself to operate through its full operating range. Once you get above 7.5 knots the stern starts to squat / bow rises a little and your wake becomes large. Just not worth it.

We didn’t have trim tabs so you could likely get an additional 0.5 knot with them. Remember the hulls used on the Helmsman offer a softer ride over typical semi displacement designs but the downside is less top end speed. Helmsman boats are also generally heavier which also helps with a softer ride but at slower speeds. The standard engine (250hp) is really all you need on the 38E and likely a better fit. The 380 is over kill in my opinion but was nice to know we had the extra power if we needed it to fight a current or tide (we never needed it).

John T

 

[HeadedToTexas]

We also have the 380 and can cruise at 9 knots, but the fuel burn eats at me and I feel better running at 7-7.5 knots. We never run wide open throttle, but as I recall it was like 13 knots during the survey.

 

[FWT]

I don't own one. Yet. Very likely I will.

If you have not seen the performance charts, they are on the website. Scroll down and click on the visible chart to see a series of them.

https://www.helmsmantrawlers.com/about-helmsman-trawlers/

 

[FWT]

Also, if you talk to Scott or listen to his commentary on various Youtube clips, he is pretty unapologetic about the hulls being much closer to displacement than speedboats, along the spectrum of semi-displacement. If you want something sturdy to handle snotty weather this the end you want. If you want speed in smooth weather, the other end may be better for you, with something like the American Tugs or Nordics, or Swift Trawlers.

 

[Helmsman]

Thank you, John. That helps with an understanding of the top speed for the 38E with the 380. By the way, I understand very well the dynamics of WOT on fuel usage! My last boat had two V8 gas engines. So, I certainly paid through the nose when I did, on occasion, need to step on it. Would be interesting to see the speed/fuel curves for the various engine options for the 38. Hopefully others will post here to get an idea.

 

[Helmsman]

Thanks, FWT, for the link to the charts and the comments. I like the 38E. Just want to gather some more information prior to possibly taking the plunge. My travel would be on the Tennessee River south through the gulf and possibly up the east coast of Florida. I don't think I would get further than Virginia. I do want to be able to travel upriver against the various currents you run into.

 

[Water Music]

We have ordered a Helmsman 38E for delivery in spring 2021. We come from a sailing background so speed was not an issue for us and top speed on our current boat is just over 7 knots. After discussions with Scott and doing a bit of research on line we went with the standard 250hp engine. After reading this discussion thread I am happy with our choice.

 

[Fletcher500]

We have the 43 with a 380hp Cummins like John. Agree, 250 hp would be fine. However, There are times when I do like the extra hp for short duration bursts to clear another boat for give way situations or to enter bars with following seas where I like to get closer to the speed of the swells and reduce fish tailing.

 

[FWT]

We have the 43 with a 380hp Cummins like John. Agree, 250 hp would be fine. However, There are times when I do like the extra hp for short duration bursts to clear another boat for give way situations or to enter bars with following seas where I like to get closer to the speed of the swells and reduce fish tailing.

Fletcher, you have more length for more hull speed, but a bit more weight. I am curious what you see at 80% WOT (max fast cruise speed) and WOT?

 

[Helmsman]

Anybody have the 425 hp or data for it? This set of posts has been very helpful. Thanks!!

 

[Fletcher500]

FWT, my numbers are very similar to those posted on the Helmsman website in regards to speed/rpm, etc.

Helmsman, I was originally going to spec a 425hp, but there wasn't one available for the build timeframe so I went with the 380hp. IMO, that is plenty for these boats.

Side note: I did my annual WOT test yesterday with 3/4 fuel and water and a relatively clean hull. We have added a lot of weight over the past 3 years and I can still make rpm. Scott did a good job matching the prop size/pitch to the boat.

 

[Nomad Willy]

Yup, everybody seems to add weight to boats.
Like Jay N mentioned in a very recent post.
Very little “take it off .. we don’t need that”.
And then there’s hull fowling and perhaps a weak fuel pump.
It’s all uphill re weight as we go fwd. And if you asked a NA how much power your boat needed the first thing he’s ask is “how much does she weigh”?

“Annual WOT test” .....
I think three to five times as frequent wouldn’t be too often. I do it usually several times a year. If one’s engine is in good working order w all maintenance performed on schedule a minute or two of WOT is fly stuff for one’s diesel engine.

I usually run just long enough to get a good reading on the tach. But I should run longer ... perhaps two or three minutes. Three minutes at full bore means “all is working well”. Then you can go where an engine quitting would be worse than inconvenient ... with full confidence .. or as close as you’ll ever get.

I think the fear of running a diesel engine near or at full output comes from our extensive experience w gas engines in out cars. They are extremely quiet compared to diesels but diesels are probably more capable to run full bore for some time than our well behaved gasoline engines. Diesel engines make noise, so much so that it’s a bit scary. BUT they’re built for it. The pistons in your car engine are frail looking things and light compared to your boat’s diesel engine.

 

[firehoser75]

I agree Eric. My Cummins 6BTA 330 hp M3 is rated by Cummins to be able to run at WOT for 1 hour out of every 8 hours of run time. Therefore, running at WOT for a few minutes once in a while should not cause any issues with a well maintained, properly warmed up engine! Because I run mine at about 1/2 throttle most of the time (varying it a hundred rpm every so often), running up to 80% throttle at the end of a longer run (over 5 hours) for 10 minutes or so and then to WOT for a few minutes is actually good for the engine (systems -eg. turbo) and allows me to check for potential developing issues (like rising temps, vac gauge etc.).
It does get loud

 

[Fletcher500]

Not sure where in my post you guys got the idea that running to WOT is a bad thing. Do it every week if you like to, no worries.

 

[Helmsman]

I agree Eric. My Cummins 6BTA 330 hp M3 is rated by Cummins to be able to run at WOT for 1 hour out of every 8 hours of run time. Therefore, running at WOT for a few minutes once in a while should not cause any issues with a well maintained, properly warmed up engine! Because I run mine at about 1/2 throttle most of the time (varying it a hundred rpm every so often), running up to 80% throttle at the end of a longer run (over 5 hours) for 10 minutes or so and then to WOT for a few minutes is actually good for the engine (systems -eg. turbo) and allows me to check for potential developing issues (like rising temps, vac gauge etc.).
It does get loud

If I end up going this route, there will be a learning curve for me. I had twin Crusader 300 hp gas engines on my last boat.

 

[Durant F]

Wow...
Twin 300hp gas...
You’re in a different tax bracket than me to run those!
The Cummins would seem like a Prius by comparison.
Happy boat hunting.

 

[arthurn]

I have a Helmsman 2017 38E with a cummings QSB-6.7 480 hp. I cruise around 7.5 knots. WOT with trim tabs is 14 knots as measured by gps at time of survey. Bottom was clean tanks were only about 1/4 full.

 

[Helmsman]

I have a Helmsman 2017 38E with a cummings QSB-6.7 480 hp. I cruise around 7.5 knots. WOT with trim tabs is 14 knots as measured by gps at time of survey. Bottom was clean tanks were only about 1/4 full.

Thanks. Did you mean 380hp? I thought the largest engine was a 425hp.

 

[HeadedToTexas]

My Cummins 6BTA 330 hp M3 is rated by Cummins to be able to run at WOT for 1 hour out of every 8 hours of run time.

To me, the issue is more about Cummins rating their engines to not have to run WOT every so often rather than be able to run... My preference is to run at cruising speeds for hours or days on end without having to run up to WOT and burn a ton of fuel every so often. What am I missing?

 

[arthurn]

Thanks. Did you mean 380hp? I thought the largest engine was a 425hp.

Helmsman

Taken from the pre-purchase survey.
Engine make Cummins Model: QSB-6.7 Fuel type: Diesel
Engine Horsepower: 480 Rated RPM: 3300 Engine hours: 185.0
Engine serial #: 74072036 Oil analysis: Performed Oil Placard: Yes
Induction: Turbo /Aftercooler # of cylinders: 6 . Alternator: 12V 80 A

 

[Helmsman]

Helmsman

Taken from the pre-purchase survey.
Engine make Cummins Model: QSB-6.7 Fuel type: Diesel
Engine Horsepower: 480 Rated RPM: 3300 Engine hours: 185.0
Engine serial #: 74072036 Oil analysis: Performed Oil Placard: Yes
Induction: Turbo /Aftercooler # of cylinders: 6 . Alternator: 12V 80 A

Thanks. I didn’t know they had a 480.

 

[rslifkin]

The QSB 6.7 goes all the way up to 550hp, although I don't know if Helmsman has ever installed one at that rating.

 

[Nocanvas]

HP 2008 Mariner Seville Pilothouse 37

Thanks. Did you mean 380hp? I thought the largest engine was a 425hp.

We have a 480HP Cummings (love it) we just splashed after a haul out last week. Full water, 1/2 fuel & running on or spare prop while we wait for The Prop shop in Everett,WA. to finish modifying our Nibral prop which should get us more top end while keeping within our engine RPM requirements. On our spare prop our WOT max speed was 12.4 knots (with trim tabs). There are some differences to this year of boat which Scott addressed in the newer Helmsman 38E.