DE 25 Performance #s

[David Sours]

I had a chance to get the boat out and run it by a friend with a camera. There are some new pictures posted on the gallery
http://gallery.bateau2.com/thumbnails.p ... 148&page=2
The pictures at the bottom show some of my runs....#2 in my window corresponds to 2000 rpm, #3 = 3000 rpm,
#4 (hard to see) = 4000 and #5 = (guess what?) 5000 rpm. I also made runs at idle, 1000 rpm, and WOT, 5750 rpm. The boat weighed 3570 lbs (me, 50 gal fuel, anchor & rode, door, cushions, canvas, Coast guard stuff, "camping gear" etc.) It's a
115 E-Tec with a long shaft (2.25 : 1 gearing, I think) the prop is 3 bladed 15 x 15 SS. Here are the #s:

RPM Knts GPH
Idle..................600....................1.7............................0.18
1000...................3.4............................0.29
2000 (#2)..............6.9............................1.18
3000 (#3).............12.1............................2.69
4000 (#4).............18.0............................6.5
5000 (#5).............24.1............................9.1
WOT 5750...................27.2...........................11.25
These aren't "absolutely accurate". The digital gauges, reading to the 100th, or, in the case of the tach to 50 rpm, "bounced" around a little. The fuel at 3000 rpm, for example, would read between 2.66 and 2.71. To my eyeball it seemed to stay on 2.69 the longest. Same with other numbers. I did get some comments about how much of the nose was out of the water at 4000, 5000 and WOT. I just think thats normal for a light boat going flat out. It felt fine. Never "squirley".
This supports my plan and my "target" to run the boat between 3000 and 3500 rpm and 14-15 knots.

[TomW]

Numbers look good David. Topping out at 5750 isn't bad at all. Those are good cruise numbers.

[ks8]

Nice...

[tech_support]

Looks very good, both the fuel burn and the trim angle

[sitandfish]

..I did get some comments about how much of the nose was out of the water at 4000, 5000 and WOT. I just think thats normal for a light boat going flat out. It felt fine. Never "squirley"...

Performance is what counts and she certainly has that. I think because of the added bow stem people will naturally look for this boat to adopt a running attitude of a displacement hull. It simply means that you will look great at displacement speeds and you will blow the doors off any boater that thinks that you actually are one.

She sure is a beauty!

[fishingdan]

A beautiful boat. Well done!

This is one of those posts that reminds us of the great benefit of these designs. Where else do you see a 25' boat of that style running those numbers with a 115hp engine???? Given the forecast for fuel prices later this year, this a huge benefit of these designs.

The running angle looks fine to me. You might want to consider adding a chine fender/spray rail on the aft hull sides. It is hard to tell from the pics, but it looks a little bit like water is hugging the aft hull sides a bit too much. Maybe it is common with the DE25 hull design. In my case, it was the result of a chine that was rounded a bit too much.

[TomW]

David my first look at your boat was it is beautiful, but! To much spray in the 3000 rpm range that boat is going to be wet in heavy weather. I don't know what kind of spray rails you put on her but you might want to revist that issue.

But man that is a beautiful boat!!!

Tom

[topwater]

Tom i dont think he put any spray rails on the boat. I have seen a number of de's and
nv's built without them and i dont know why they leave them off. I think Bill S
in florida had a de 23 and left them off also.

[Spokaloo]

Where he's gonna use her, she won't really need sprayrails. If it is rough enough to blow water up from the spray that's present (still below the gunnels), the water is going to be snotty enough to require slower speeds.

Or just get in the cabin!
E

[Knottybuoyz]

Those are pretty good numbers compared to my 25' express cruiser with a 275 HP Volvo Penta Duoprop. At nearly 5000 lbs loaded it's a heavy 25 footer. It's a planing hull so the numbers look weird but based on my experience it'd be something like this:

speed is kts, mileage is gallons per hour

650.....5.....?
1000....7.....?
2000....12....?
3000....23....6.6
4000....33....12 (approx.)
5000....39....20 (estimated)

The sweet spot seems to be around 3100 RPM and approx. 2.5 mpg or 1 litre/kilometer

I'd swap for the DE25 anyday!

Nice job.