Engine performance curves?

Hi all,

Looking at options on a new 38E, and am wondering if there is engine performance data available from anyone for engines beyond the 250 (which has nice data from the OLN review)?

Considering the 380 is now the standard engine, and there are 3 other larger options (425, 480, 550), I'd love to know some solid stats on their performance in the 38E...

Thanks for any info/thoughts!

Try: https://boatdiesel.com

Thanks, but hoping for performance of the engine actually in the 38e (rather than just basic engine power curves from the engine manufacturer).

I'd think the hull manufacturer would have installed performance data for the larger engine (and appropriate larger prop) combinations...

subcloner said:

Thanks, but hoping for performance of the engine actually in the 38e (rather than just basic engine power curves from the engine manufacturer).

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So what you’re really looking for is boat performance data, not engine performance curves.

And some of us have no idea what a 38E is, so it may be beneficial to rephrase the inquiry overall(?).

chriscritchett said:

So what you’re really looking for is boat performance data, not engine performance curves.

And some of us have no idea what a 38E is, so it may be beneficial to rephrase the inquiry overall(?).

Click to expand...

And some may not know what a 250, 380, 425 ….. is.

And as noted above, you want real world boat performance data, not engine power curves. That is hard to come by.

I have never seen manufacturer supplied boat performance curves published, always by third parties.


David

I am surprised that this information is not available from the builder. The Sabre website has performance data for all boat and engine combinations. Performance data for a Sabre 38 with one of the three engine choices is attached.

My experience has been that the performance data accurately reflects real world performance with a clean bottom.

oguidry said:

I am surprised that this information is not available from the builder. The Sabre website has performance data for all boat and engine combinations. Performance data for a Sabre 38 with one of the three engine choices is attached.

My experience has been that the performance data accurately reflects real world performance with a clean bottom.

Click to expand...

Check the fine print on those numbers. A lot of times (perhaps most of the time) those performance numbers are predicted, not measured. And when they are measured, it's invariably with a very light boat. I would give very low weight to any published boat performance numbers. I have just heard too many where I know it's wrong because I own or have owned the same boat and got nothing like what's reported.

twistedtree said:

Check the fine print on those numbers. A lot of times (perhaps most of the time) those performance numbers are predicted, not measured. And when they are measured, it's invariably with a very light boat. I would give very low weight to any published boat performance numbers. I have just heard too many where I know it's wrong because I own or have owned the same boat and got nothing like what's reported.

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I see the Saber numbers are actual measured numbers, and they have provided a lot of detail. Good on them - that's rare. The only thing I don't see is whether they did reciprocal runs and averaged to try to take out the effects of wind and seas.

Here is some info for the 250HP Cummins on a 38E. It would be great to see similar data for the other power options.
https://www.oln.world/boat-test/helmsman-38e/performance

Hi there …I’m getting 38e built w 380 Cummins and found this helpful:

https://www.helmsmantrawlers.com/wp-content/uploads/2023/08/43-38-37-Fuel-Consumption-Range.pdf

You’ll see a few graphs and two address the 38E w the now standard 380 Cummins. Hope it helps

subcloner said:

Hi all,

Looking at options on a new 38E, and am wondering if there is engine performance data available from anyone for engines beyond the 250 (which has nice data from the OLN review)?

Considering the 380 is now the standard engine, and there are 3 other larger options (425, 480, 550), I'd love to know some solid stats on their performance in the 38E...

Thanks for any info/thoughts!

Click to expand...

Sent you a PM with my own experiences with our new 38 Sedan with a 550 hp Cummins.

https://mart.cummins.com/imagelibrary/data/assetfiles/0042721.pdf

The Helmsman graphs posted above are quite useful.

The above link is to the Cummins data.

HI FWT. Your link appears to have been moved. Do you still have the data o know where to get it?

Tom-Jill-Lilly said:

HI FWT. Your link appears to have been moved. Do you still have the data o know where to get it?

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Hi there... is this the link you are seeking?

You are right. Its gone and not in any fresh link I can find.

In fact I did save the old spec sheet in a PDF. Will send via PM if I can make that work.

subcloner said:

Hi all,

Looking at options on a new 38E, and am wondering if there is engine performance data available from anyone for engines beyond the 250 (which has nice data from the OLN review)?

Considering the 380 is now the standard engine, and there are 3 other larger options (425, 480, 550), I'd love to know some solid stats on their performance in the 38E...

Thanks for any info/thoughts!

Click to expand...

I don’t have a lot of hours n my 38E, but during sea trial and repair testing, it’s quite clear that our hulls are really full displacement hulls. You can add a lot of horsepower and large trim tabs and power your way to plane. If that’s what you’re looking for, this isn’t your boat. A Beneteau Swift 35 or 41 have the power and light weight to plane. I just enjoy hull speed. You’ll get about 2.5 miles per gallon on any engine you select at hull speed.

amxr39 said:

I don’t have a lot of hours n my 38E, but during sea trial and repair testing, it’s quite clear that our hulls are really full displacement hulls. You can add a lot of horsepower and large trim tabs and power your way to plane. If that’s what you’re looking for, this isn’t your boat. A Beneteau Swift 35 or 41 have the power and light weight to plane. I just enjoy hull speed. You’ll get about 2.5 miles per gallon on any engine you select at hull speed.

Click to expand...

If it was a full displacement hull it wouldn’t be possible to exceed hull speed with any engine that would probably reasonably fit.

I don’t know this for a fact, but after 54 years of messing around with boats, to my eye the hull form looks a lot like the Wilbur 38. Performance seems very similar with the Wilbur 38 as well.

The Maine Downeast builders make many boats with similar hull lines. Deep forefoot, full built down keel, soft chine, transitioning to a flat after section. Very different from the hull form of a Krogen or Nordhavn.

“Semi displacement” is a spectrum, and this hull leans more into the displacement zone than semi-planing. On the other hand a hard chine and skeg type keel would lean more towards planing (like the American Tug hull form).

The Beneteau hull is really a more or less conventional full planing design, albeit with a very small keel seemingly solely for directional stability. The trade off is higher speeds with less fuel consumption.

FWIW the Wilbur 38 needs at least 450-ish hp to achieve a semi-planing running attitude. Those boats are sometimes powered with 800+ hp engines and can exceed 20 knots.

The Helmsman 38 hull seems to perform similarly. It seems to take at least 425 and more like 480 hp to achieve hydrodynamic lift which generates about 16 knots, and my 550 hp yields 17-18. All very similar to the Wilbur 38.

Of course fuel consumption increases exponentially once above the 7.5-ish knot hull speed. Doubling speed takes much more than double the amount of fuel.

It’s like the old hot rodder’s saying - ‘Speed costs, how fast do you want to go?’