Cruising speed

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cmedsailor

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According to the manual of VP 2030D the cruising speed of this engine is 300-500rpm lower than the maximum which is around 3500rpm. Doesn't this sound too much? Would you travel at 3000rpm and consider this as cruising speed? I almost never exceed 2500rpm.
Just wondering what you people do.
 
I have a VP 2003. I'm not sure what the max revs are or even the recommended cruising revs are. I know that a bit over 2000 revs the noise and vibration increase out of proportion to the additional speed so unless I'm in a rush it's 2000 revs and 5 knots.
 
My 2030 cruises comfortably at around 2500 giving just under 6 knots. On a saildrive so well propped and will happily run up to maximum revs giving around 7.4 knots.

So 2500 well within capability. Quiet smooth and economical. But plenty in reserve if needed
 
There seems to be a general agreement that we motor at a speed we are comfortable with, which is probably about right. I usually run my 2030 at about 2500 but had to do 2700 for 24 hours once with no problem. I know it's been run up to 3400 but prefer not to try.
 
Recently encountered an otherwise well looked after Volvo 2000 series diesel with about 800 hours, reluctant to start and smoky when running. On disassembly for a rebuild the main problem was bores glazed - the verdict was ".... not run hard enough".

I regard 2800-3000 rpm as cruising on a Yanmar that peaks at 3400. Time will tell how long it lasts, but it's near the hours of the abovementioned Volvo already, and starts instantly and makes very little smoke.
 
I'm sure you're right, but 2800+ is pushing us along faster than I often require.

There seem to be an awful lot of John Wilsons in the world - my Doctor's got three on his list.
 
Dead right. No point in having a big engine and running slow. Get a smaller one if you don't need the power. My Vetus M4 peaks at 3500 RPM but runs most of the time at 3000. Sweet as a nut! No smoke, no overheating. Uses less fuel at 2500RPM of course but runs off a sniff of the barmaids apron anyway! You are all killing your engines with kindness!!!
 
Mine has done over 2500 hours and no sign of bore glazing. These engines are fitted to hundreds of charter boats that do more in a year than many private boats do in a lifetime. It is the short runs every so often interspersed with long periods of idleness that kills marine engines.
 
New engine, only done 100 hours over 2 years. Yanmar 3ym30 IRRC. Generally do 2-2500 revs with around 5kts, which is very smooth & quiet. But like to exceed 3000 from time to time to prevent glazing and have done 3300-3400 for several hours to beat tide gates. The grill pan rattles a bit but it drives her well.
 
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We have an MD2030B. If I run at 3000 rpm for more than 10 minutes the overheat alarm sounds! Probably because the boat is over propped. Doesn't bother me. The boat doesn't go any faster at that engine speed. Only difference is the transom step is awash!

[/ QUOTE ]We have an MD2030B as well, and we can run it flat out for as long as wish without it overheating. There must be something wrong with your cooling system (Primary or secondary).

In practice we run it at about 2500 for most of the time, but I don't worry about having it on max if needed - except that it drinks diesel and I'm tight with the diesel bill!
 
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