Mercury Diesel Sterndrive test ride

[pelican]

Originally Posted by kmoose

Even if the cost was a wash, which I am doubtful, the extra weight and reduced performance at cruise and top end would be a deal breaker for me. The slowest I cruise is 24 knots and on a good day 28-30.

Personally I love diesel power but not on small boats. I've seen them on 23' boats and other than fuel economy they just are not very impressive.

"cruise is 24kts and on a good day 28-30" ?

people often make a few mistakes - first one: over estimate their abilities

second: over estimate the speed of their ship


I believe you've made claims concerning speed before - I would have to see this cruise speed claim

[Islandtrader]

Originally Posted by Fr. Frank

I got a ride today on a 2012 Chaparral 19' deck boat/bow rider powered by a 150 hp 2.0L turbo diesel sterndrive.
Top Speed - 48 mph
.

Call me doubting Thomas...48 mph...I just don't see this happening...I can just barely get 50 on a good day and on ruff water also.

[kmoose]

While there is no need to defend my cruise speed spec here as many on this board know what speed and cruise capabilities of my full dressed Tsunami are...... Here is a pic of my plotter at WOT with 2 people and a 60 gal of fuel. Also note that my power is a tired ol 2004 Suzuki 4 stroke 250 swinging a 16x21x3.

[kmoose]

Off my new plotter at low cruise.....

[Islandtrader]

Originally Posted by kmoose

While there is no need to defend my cruise speed spec here as many on this board know what speed and cruise capabilities of my full dressed Tsunami are......

I have chased after Moose and I know his sled flies...its to bad my wife was screaming slow down after I jumped his wake and wanted to pass him...

[FLexpat]

ok - this piqued my curiosity and I ran some numbers...
Merc says at 4200 it puts out 370HP and at 3000 it puts out 330HP/572ft-lbs and uses 7.8gph.

If my prop slip numbers are ok and the performance numbers posted here for various Sceptres are somewhat close then WOT would be low 50's, cruise in the low 40s (mph) and fuel economy should be near 6mpg at cruise. One challenge might be that, having so much power even at the low end, idle & trolling speeds might be faster than most want. A 40mph (or even 35mph) cruise would be pretty tough for me on a lot of days - I dont bounce back from that kind of beating as well as I used to.

I have a Bravo 1X Diesel drive going in my Sceptre so all I would need is the motor - I would love to be a guinea pig if someone else would fund it! All that said, the parts would scare me. That motor is built by VW for only Marine apps, Touareg, Audi A8&Q7 and the Porsche Cayenne. I'm thinking an ECM or a turbo would pretty be hard to get (and harder to get properly installed) in most places even with a healthy checkbook.

[kmoose]

Originally Posted by pelican

"cruise is 24kts and on a good day 28-30" ?

people often make a few mistakes - first one: over estimate their abilities

second: over estimate the speed of their ship


I believe you've made claims concerning speed before - I would have to see this cruise speed claim

Seeing is believing but feeling is real....

[kmoose]

30 knot cruise day.....

[kmoose]

24 knot day......

[jdm61]

The Mercury numbers for the 3 liter 260 hp V6 which is realistically a more apples to apples comparison with a 250 4S outboard, is that same 24-25 knots at 8.6 mph in a Sea Ray 250 SLX with an manufacturers claimed empty weight of 5900 pounds and a Mercury claimed "as tested" weight of almost 7700 pounds.Althou the prices seem to be coming down a little, cost is still an issue with the diesels and weight is an issue in boats not originally set up for I/O propulsion,but that would also be the case with a gas I/O setup. The one "problem" with the VW/Mercury engines is that it is almost like the old days where you had to go with a big block gasser with you wanted 300+ hp. That is obvious not the case with the modern outboards and small block Chevy MPI inboards today. With that said, the V6 VW and inline 6 BMW's which are realistically designed to replace small block V8's in lower state of tune much like the current 4.5 liter V6's gassers are, weigh about 200 pounds less in bobtail form than a 300 hp 5.7 liter V8 and 90 pounds less than the comparable 250 hp 4.5 liter V6. The 330/370hp 4.2 V8 weighs almost 200lbs less than the 380 hp 8.2 big block and maybe 60 pounds more than the 350 hp 6.2 liter small block, all with closed cooling systems. The 2 liter I4 which you can get in flavors from 115 to 170 hp weighs about 60 pounds more than the 3 liter gasser 135 hp and about 200 less than the older 180/220 hp 4.3 liter V6. These engines are inboards and the slot right into the spots of the engines that they are designed to replace. If you need crazy HP and gasser weight at the attendant high price, you would probably want to look at one of the Duramax conversions from the Swedes or Banks Engineering. You bobtail block weigh would still be about 100 lbs less than a 502.

With all that said, it is still really great time to be looking for a new outboard.