Expected Performance from.......

D

David M

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a 40 foot Sea Ray Express (not Sundancer) with twin 7.4 Mercruiser Bluewater series engines. 340HP per side.

Possible swap for Saint Max, but I'm thinking it is WAY underpowered. I like a 22 knot cruise.

What say you?
 
David,

With 10" more beam, a couple thousand more pounds, the same engiens and v-drives instead of straight shafts, I cruise at 23-24+ knots, which is faster than what most of the diesel guys are comfortable with. I average .72 mpg

I regularly goose the throttles in close-quarter manuevering, but you already know how that goes...

At the risk of starting a fight, I drove a diesel Sundancer across the lake yesterday, and since I wasn't paying for the fuel, I missed my gasser 90% of the time. (the response at the dock can't be beat though)
 
quote:
Originally posted by SLW

David,

With 10" more beam, a couple thousand more pounds, the same engiens and v-drives instead of straight shafts, I cruise at 23-24+ knots, which is faster than what most of the diesel guys are comfortable with. I average .72 mpg

I regularly goose the throttles in close-quarter manuevering, but you already know how that goes...

At the risk of starting a fight, I drove a diesel Sundancer across the lake yesterday, and since I wasn't paying for the fuel, I missed my gasser 90% of the time. (the response at the dock can't be beat though)

Click to expand...


7.4's, 8.1's, or 502's. I did not see it in your bio, or if it's there, I missed it.

How is the noise. Saint Max is a bit louder at cruise because the 6.2's cruise at 4K v. 3400 RPM's.
 
I'm assuming that a 400EC with 340 HP has the same 7.4 Bluewaters that I have. (when Merc introduced the Horizons, they went up to 380)

Noise is fine. As I recall, about the same as my 7.4 330DA. You'll be going from a hard-top to a soft-top too, right? That helps as well.
 
...btw, the reason I prefer gas 'dancers on the water is because of excess weight at the stern and noise of the diesels. The EC of course, boasts better balance due to the fwd placement of the engines, and have a naturaly comfortale running angle in spite of heavy iron.
 
Dang Dave,
I don't even go that fast in my 24 footer most of the time.
 
Around 3400-3500, depending on load and conditions. I need some degree of tabs unless I push them up to the 3600-3700 range, but I try to avoid that.

The speed also depends on the load. Carrying full water and fuel and some guests can cost me about 2 knots.
 
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