Sealine F43 with 63p over revving?

KajLehtinen

KajLehtinen

Well-Known Member
Joined
6 Dec 2003
Messages
93
Location
Sweden, Stockholm
www.sealine.nu
Hi!

Did test my new F43 last weekend, the engines did over rev rather much, I reached 3200 rpms WOT. Fully loaded with diesel and water but no gear and only me onboard.

The Swedish diesel (boat in Germany now) has about 5% less efficiency in it (but more friendly to the environment) which I guess means that I will WOT out at 3040 rpms or so. Still high, or what does the community think?

The engines should do 2800 rpm. Its loaded with a 23" * 29" prop right now, I think the factory one was 23" * 31" prop. Dont know the difference tough.

Reprop or accept the higher WOT?


IMAG0047 by KajLehtinen, on Flickr

/Kaj
 
I would firstly be testing your tacos with a hand held rev counter as 3200 is way above the no load speed of thoses engines, what speed in knots did the boat achieve? is it both engines or just one? if all is correct it could point to wrong props, what was the speed on the sea trial when you bought the boat.

The tacos can be calibrated with a small pin probe on the back so maybe they have been changed at some point which is certain as the lcd displays fail for the hours, they are universal tacos so do need setting up.
 
volvopaul said:
I would firstly be testing your tacos with a hand held rev counter as 3200 is way above the no load speed of thoses engines, what speed in knots did the boat achieve? is it both engines or just one? if all is correct it could point to wrong props, what was the speed on the sea trial when you bought the boat.
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The boat achieved 28.5 knots now, in October when we sea trialed it we got 29.x knots.

At 2900 rpms on the tach I got about 25 knots. Both engines show the same error, also on the fly bridge If I recall correctly. I've asked the dealer to check the revs using a optical rev counter. 2000 rpms gave me about 10 knots yesterday. I got about 3.5 knots at tickover.

The dealer talked about re-pitching the props if they are wrong and asked what RPMs I wanted. Taken account for the 5% loss in Swedish diesel I replied that around 2950 rpms WOT which would make it about 2800 rpms when the boat gets to Sweden (in two weeks I hope!)

/Kaj
 
Hi,

A few weeks ago I did a 500NM 3-day trip in my (new to me) 2001 F43 with 63Ps at 650hrs: best WOT was 2800rpm achieving 26-27K with a clean bottom, full tanks, tender and fair sea conditions.

The top end speeds you are achieving do seem to be higher than I can achieve at 2800rpm which may indicate the rev counters could be reading correctly and giving you an extra few K.

I would be interested to know why your engines are over-reving, I would guess it might be due to some extent to type of fuel, possibly props/pitch, the only other thing I could think of might be gear ratios? My boat has the ZF IRM 220A1 Gearbox.

Anyway I will be interested in what the experts on here have to say!

20giqvm_th.jpg
 
KajLehtinen said:
The boat achieved 28.5 knots now, in October when we sea trialed it we got 29.x knots.

At 2900 rpms on the tach I got about 25 knots. Both engines show the same error, also on the fly bridge If I recall correctly. I've asked the dealer to check the revs using a optical rev counter. 2000 rpms gave me about 10 knots yesterday. I got about 3.5 knots at tickover.

The dealer talked about re-pitching the props if they are wrong and asked what RPMs I wanted. Taken account for the 5% loss in Swedish diesel I replied that around 2950 rpms WOT which would make it about 2800 rpms when the boat gets to Sweden (in two weeks I hope!)

/Kaj
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This probably won't help you but mine does about 5 knots at tickover. With clean bum and shiny props about 6 knots.

I never get revs that high but wot with a clean bum is probably about 27 knots, I don't go there very often, maybe only to get out of the way of something.
 
The engines you quote operate at 114% of max RPM ... with the comparable torsional forces on pistions etc., at the moment of ignition when pistons changes direction... I would no be comfortable with that!!

1) RPM counters are wrong
2) Rev Limiter is bypassed or damaged
3) Something else is wrong

It would be OK to keep the boat like this (underpropped) IF you don't operate above 2800 RPM (restrict throttle movement to 2800 RPM), and cruise at 2600 RPM or below. (We WOT at 2300 and drop 500RPM for prolonged cruise).

First thing to check is your rev counters which means you have a baseline ... if they are OK, you need to decide if the Cruise you get at 2600 RPM is what you are happy with, then, if you take above precautions, all is OK.... if not, you need to do someting....and "what" depends on the answers to the above...
 
Hey guys,

Lets get real!

#1 you cannot over rev a diesel engine. Volvo 63 has rated speed of 2,800 rpm, MECHANICAL not electronic marine engines tend to have around 10% governor droop so expect to have high idle of around 3050/3080..

#2 Where the friggin hell did the term 'tickover' come from James Watt! I was brought up on AEC's Gardners, then served my time on large engines. Then had culture shock of lerning that Americans refer to sumps as oil pans and setting tappets as doing a top set. Tickover dont even come up on my international radar, must me some sort of gasoline motor horse ****! The term is idle.....Low idle and high idle.

#3 Never, never, never, make judgement regarding prop pitch with uncalibrated tachos. Perform high idle test on your motors, warmed though, out of gear, nail the throttle, let the motor sing to you, any more than 3050/3080 once governor has stabilised (high idle) any more and you have evidence that your tacho is telling to a bunch of porkies!

#4 Fuel has ZERO impact on your engine calibrated performance period!

#5 Before you even consider any changes obtain ACCURATE data. No engine has ever been damaged running out on the droop, plenty have been totally wrecked by failing to reach rated rpm.
 
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Thanks for keeping us right LS1 !!!

don't know the 63's at all, so was not sure if mechanically governed... but now I am happier !! .. and agree that you cannot over rev to such an extent, hence suspecting tacho's.
 
Rather than shooting from the hip I actually looked at a Volvo 63P data sheet........What a worthless waste of marketing gobbledegook produced to impress potential owners at shows and thats about all! I am too used to stuff from Cat, Cummins and Detroit which hold meaningful data. No mention of any high idle figure, remember the difficulty finding max EGT for this motor a while back. Thankfully data sheet has no mention of 'tickover' either. Some manufacturers even quote sound pressure on their data sheets which is real useful. A so called 'quiet' diesel engine is akin to a quiet hand grenade at WOT.

Ok, there is just sufficient data for slide rule Sam in the builders engineering office to put a propeller calculation together. Sam knows vessel will be operating in Northern European seawater ambients, he knows that the 63P 370 is actually 355 Hp (unlike the electronic D6 370 which is 370, and has pretty much isochronous governing, confused yet?) we have prop aperture data so all Sam needs to do is calculate pitch required to absorb 85.90% of 355 Hp @ 2800 engine rpm. That IS of course if Sam has practical experience, he will know that a new vessel clean with full tanks will get heavy as owners add toys and with weed growth will gradually pull engine back to rated rpm. Sadly you are govered by propeller law, remember props move boats not engines, and attempting to absorb 100% of the available engine power when vessel is new and clean is a recipie for future engine problems.
 
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Kaj, today I removed the props and p brackets from PRHs boat off this forum, interestingly they are 23x31 pitch so maybe thats your answer to te over revving, but as I and latestarter have said start with a hand held taco to set up the boats tacos first.
 
mjf said:
FWIW - I saw 2800 WOT revs and 30 knots with clean bum and polished props with 100% fuel and water and rib tender with O/B on the swim platform w/e before last.

I was well pleased - jumped over the hump like a racehorse too :-)
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30k at 2800, I knew I should have told Hurricane to leave all his PC equipment at home!

Where were you, what was the sea state, were you getting 3k help from wind/tide! I'm interested to know, as you know I only recently bought the boat so still on a learning curve! She sounds quite sweet at 2600, my top end set point.

John
 
volvopaul said:
Kaj, today I removed the props and p brackets from PRHs boat off this forum, interestingly they are 23x31 pitch so maybe thats your answer to te over revving, but as I and latestarter have said start with a hand held taco to set up the boats tacos first.
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Good advice as always but is it likely that both tacho's would be reading incorrectly? Worth checking of course. I will be next on my boat on Friday, this thread has prompted me to check what props I have fitted!
 
John100156 said:
30k at 2800, I knew I should have told Hurricane to leave all his PC equipment at home!

Where were you, what was the sea state, were you getting 3k help from wind/tide! I'm interested to know, as you know I only recently bought the boat so still on a learning curve! She sounds quite sweet at 2600, my top end set point.

John
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John i think MJF has a princess 38 if is the same one that he had at the forum meeting , perhaps a bit more nimble than an F43 , (less room though ;) )
 
mjf said:
FWIW - I saw 2800 WOT revs and 30 knots with clean bum and polished props with 100% fuel and water and rib tender with O/B on the swim platform w/e before last.

I was well pleased - jumped over the hump like a racehorse too :-)
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Well pleased mmmmmmmmmmm.

Do not know what the engines are, however IF they have rated rpm of 2,800 rpm and you are just squeaking 2,800 rpm clean, at the beginning of the season I would be concerned, extremely concerned. Pulling 100% of the power engine has to offer at the beginning of the year it follows that as the season goes on the situation will progress with the engine suffering gross overloading as hull becomes harder to drive. Is this a situation to be proud of?
 
Data>Knowledge>Wisdom

Latestarter1 said:
Well pleased mmmmmmmmmmm.

Do not know what the engines are, however IF they have rated rpm of 2,800 rpm and you are just squeaking 2,800 rpm clean, at the beginning of the season I would be concerned, extremely concerned. Pulling 100% of the power engine has to offer at the beginning of the year it follows that as the season goes on the situation will progress with the engine suffering gross overloading as hull becomes harder to drive. Is this a situation to be proud of?
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[Rant mode on]

Suspect too many new boats today are designed for top performance under "show" conditions and with the magical 30 knot performance target reached. (Because it sells)... but then we load our boats up with surprising ammounts of gear (which would make a showboat look cluttered with limited ofstorage) and go cruising under the belief that the engine(s) still will reach WOT....and we do the 2-400 RPM throttle back for cruise (because we do not use WOT)... Then mother nature kicks in with what she does best !!! ... growing things onto fixed structures!!... which does not help hydrodynamics (hull moving through water). Before you know it, your conservative cruise RPM actually is you engine(S) WOT (Despite throttle handles not being pushed to the stops)... WOT = Full Fuel

Couple that with our "modern" expectations of leaving the boat for weeks, then starting her up and going for a "spin"...... expecting her to behave as a "modern machine" (despite her being in a hostile & corrosive environment).

Net result is overloaded engines, with excessive stresses (they are designed to reach a certain RPM at a given fuel injection to the cylinder). More fuel = bigger bang ... however if the bang is above design intent at given RPM, you get excessive stresses (and poor fuel combustion)..... net result is engine replacement (as they are not re-buildable) before 1000 hrs are passed.

[\rant mode off]

Sorry generalising too much now ..... so going back to my amber liquid now...
 
Divemaster1 said:
[Rant mode on]

Suspect too many new boats today are designed for top performance under "show" conditions and with the magical 30 knot performance target reached. (Because it sells)... but then we load our boats up with surprising ammounts of gear (which would make a showboat look cluttered with limited ofstorage) and go cruising under the belief that the engine(s) still will reach WOT....and we do the 2-400 RPM throttle back for cruise (because we do not use WOT)... Then mother nature kicks in with what she does best !!! ... growing things onto fixed structures!!... which does not help hydrodynamics (hull moving through water). Before you know it, your conservative cruise RPM actually is you engine(S) WOT (Despite throttle handles not being pushed to the stops)... WOT = Full Fuel

Couple that with our "modern" expectations of leaving the boat for weeks, then starting her up and going for a "spin"...... expecting her to behave as a "modern machine" (despite her being in a hostile & corrosive environment).

Net result is overloaded engines, with excessive stresses (they are designed to reach a certain RPM at a given fuel injection to the cylinder). More fuel = bigger bang ... however if the bang is above design intent at given RPM, you get excessive stresses (and poor fuel combustion)..... net result is engine replacement (as they are not re-buildable) before 1000 hrs are passed.

[\rant mode off]

Sorry generalising too much now ..... so going back to my amber liquid now...
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Kind of find myself in violent agreement.
 
Blimey it was not a sea trial - just popped to Cowes in calm conditions with spring tides at approx HW.

When we did a trial in Plymouth before hand over SHMBO did 32knots SOG without 100% fuel and water and no gear - I cannot remember the rpm.

I have found now that after a shampoo and haircut we easily reach 2800rpm and this maybe rises a little further if left 'flat out' once the fouling gets back esp on the props then 2800 rpm gets harder to see and falls to 2600 as the season progresses.

My point was with a heavily loaded boat I was happy to see the measurements easily reached which was why I then backed off and proceeded at a comfortable 2200rpm and 18/20 Knots for last 2/3 miles.

I cannot recall seeing much more than 2900 or so when left WOT for a long period
 
mjf said:
Blimey it was not a sea trial - just popped to Cowes in calm conditions with spring tides at approx HW.

When we did a trial in Plymouth before hand over SHMBO did 32knots SOG without 100% fuel and water and no gear - I cannot remember the rpm.

I have found now that after a shampoo and haircut we easily reach 2800rpm and this maybe rises a little further if left 'flat out' once the fouling gets back esp on the props then 2800 rpm gets harder to see and falls to 2600 as the season progresses.

My point was with a heavily loaded boat I was happy to see the measurements easily reached which was why I then backed off and proceeded at a comfortable 2200rpm and 18/20 Knots for last 2/3 miles.

I cannot recall seeing much more than 2900 or so when left WOT for a long period
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The difference beween a happy motor and plain killing it is a real fine line. You are propped on the 'edge'. If you can make 2,900 life is good and your engine loading is around the magic 90% however when all you can make is 2,600 later in the season your engine loading has rocketed to around 150% dependant on the 'real' prop exponent of your particular vessel.

At 2,600 WOT your EGT's will start to become real nasty. Boaters tend to do more hours and run harder in the U.S. Fitting boost and pyro's is normal practice. The combined ISSPRO Turbocator is a useful instrument if you want to live life on the edge.
 
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