53 fuel burn?

[hatterass]

i saw on the boats for sale page a 53 MY that said it burned 29gal/hr. is that for each motor and at what TRUE speed is the boat running? I am looking at a 53YF and have heard a lot of different stories. the boat has 871ti.

also I was speaking to someone els that said that I should get the boat stabilized. any thoughts on the stability of the boat with out them.
Dave

[Dave Phipps]

Dave,

My 53 Classic Motor Yacht with 8V71TIs burns 29 gph TOTAL between the two engines and the 15 KW generator, at about 1900 rpm.

As for stabilizers, they do make a difference, but I would suggest that even without them you'd be happy with the 53 hull. That said, you'd be happier or happiest with them! They really do make a pronounced difference.

Dave

[Capt K]

Hatterass, the stabs would be nice, but if you're mostly going to be cruising our area, they are hard to justify cost-wise. You'll be thrilled either way! Just get that big hunk of iron counterweight reinstalled in your current vessel and get this show on the road.

K

[MikeP]

This has been published a couple of times here for the 53 w 8v71Tis. I believe Sky posted it originally. I copied it and saved it to my "boat" files. Fuel burn is for both engines together.

RPM Knots GPH Gal/NM
0640 - 6.3 - 1.8 - 0.3
1060 - 8.7 - 8.0 - 0.9
1100 - 9.1 - 9.0 - 1.0
1200 - 9.3 - 10.4 - 1.1
1400 - 10.0 16.2 - 1.6
1600 - 10.8 23.4 - 2.2
1700 - 10.9 27.0 - 2.5
1920 - 15.5 34.2 - 2.2
2200 - 18.3 44.4 - 2.4

[first230sl]

This is very interesting. Clearly this boat gets up on plane somewhere between 1700 and 1920 RPM.

I have a 58YF with the same engines - it never gets up there. The speed increases pretty much linearly with RPM. My speed curve is as follows:

900 : 7.2
1000 : 7.7
1100 : 8.1
1200 : 8.7
1300 : 9.5
1400 : 10.1
1500 : 10.6
1600 : 11.1
1700 : 11.7
1800 : 12.4
1900 : 13.1
2000 : 13.9
MAX : 15.4 (port at 2190 RMP, stbd at 2130 rpm)

I've asked this before but don't recall hearing back. Does anyone with a 58YF manage to get the boat up on plane? Do you get a better top speed than I do? Or is it about the same?

Just had the bottom stripped down, faired and re-painted. No difference, really, to speed. I do notice that it sits a little low in the bow and a little high in the stern. That could make it hard to plane.

This has been published a couple of times here for the 53 w 8v71Tis. I believe Sky posted it originally. I copied it and saved it to my "boat" files. Fuel burn is for both engines together.

RPM Knots GPH Gal/NM
0640 - 6.3 - 1.8 - 0.3
1060 - 8.7 - 8.0 - 0.9
1100 - 9.1 - 9.0 - 1.0
1200 - 9.3 - 10.4 - 1.1
1400 - 10.0 16.2 - 1.6
1600 - 10.8 23.4 - 2.2
1700 - 10.9 27.0 - 2.5
1920 - 15.5 34.2 - 2.2
2200 - 18.3 44.4 - 2.4

[mike]

Murray,
FWIW, your numbers are the same as our 53MY with 8v71Naturals. Are you running Naturals or TI's?

[Pascal]

murray

you're overpropped for your load or your engines need to be tuned as you're short of rated rpm (2300) at WOT... assuming your tachs are accurate.

I'd start there...

[Pascal]

murray

you're overpropped for your load or your engines need to be tuned as you're short of rated rpm (2300) at WOT... assuming your tachs are accurate.

I'd start there...

[REBrueckner]

Before changing prop dimensions to gain RPM, see if your throttle controls are set up properly.

With engines OFF, put your throttle controls in WOT position. (You could also do this underway with someone else steering.) Then check the fuel control lever on each engine. If you can still move the fuel control lever (where the throttle cables connect to the engine) forward by hand, then you have inadequate movement in your controls. Maybe the Morse controls need adjustment or cables there are loose, maybe the cables at the synchronizer need adjustment.

But use caution, because if you adjust things willy nilly, you may get the extra RPM but lose low speed idle.

[first230sl]

Mine are TIs.

I might be a bit overpropped. I did the WOT no load vs. WOT under load test to see the difference recently. I left the numbers on the boat but will grab them next time I am down there.

While I may indeed need to remove a bit of prop bite, I am still curious as to whether others finds that their 58YF's don't get up on plane. If other find that they do, then I will start looking around for possible causes. Just don't want to waste my time if this is normal for the boat/engines.

Thanks!

Murray,
FWIW, your numbers are the same as our 53MY with 8v71Naturals. Are you running Naturals or TI's?