Sealine F43 with 63p over revving?

I'm not sure I understand.

I was told ages ago

1. Do not idle under no load conditions - so when leaving a berth I single up, start and in gear straight way.

2. Its good to use WOT occassionally for short periods

3. Using low rpm will glaze the cylinders


These days I generally like to cruise at 18/20 Knots and usually blast the last 1 mile before the harbour steaming at either WOT or nearly WOT.

If the weather is nice we like to cruise at 8/9 knots and enjoy the journey. Again nearly always open the throttles for the last bit before home.


Am I killing the volvo's - what should I be doing that will improve the performance/reliablity/longevity.
 
When I bought this 410 2 years ago she did 29knots flat out, but pulled nearly 3000 rpm which is 200 more than she should, and yes ive had a hand held taco on so I know its right, but after 6 months its down to 2800 and less as time goes on. I did think about having the props tweaked another inch on the pitch which would give another knot when shes clean, but load her up even more for the rest of the year.

A free under load revving engine will return more mpg than an overloaded one and last longer, owners should ignore the 30 knot adverts and use there boat for what it is and enjoy it, lets face it who wants to run along at wot most of the time especially when they visit the fuel barge after.
 
Sounds sensible to me - the 63P's seem fairly sturdy lumps.

Like MJF, I think it's good to go WOT occasionally and to vary throttle positions. Having had KAD300's on my Targa 34 which performed very well, I was pleased with the performance of my F43, we had to do a long 500NM trip recently in a fairly tight weather window and the engines just seem to like 2600, no technical reason, you just get a feel, if it was flatter and I held them WOT for a while I reckon I might have seen 2900 and possibly 28k but who cares - it's in the Med now so she can have a bit of a rest, happy days!
 
We have a very different engine to the volvos but for me the "feeling" is 3800 rpm. the engine is rated at WOT 4500 RPM (although i have only ever seen 4300) but at 3800 we are on 34 kts and everything feels right.

for us the hull isnt performing that well until about 28 kts and believe most efficient for the boat to be at around 3600 rpm which is about 32 kts. (ish)

still wondering about changing the prop on ours but sometime i think better the devil you know... if we start playing with props is it the start of a slippery slope and maybe changing the way the boat handles which is mostly perfect for us!
 
z1ppy said:
We have a very different engine to the volvos but for me the "feeling" is 3800 rpm. the engine is rated at WOT 4500 RPM (although i have only ever seen 4300) but at 3800 we are on 34 kts and everything feels right.

for us the hull isnt performing that well until about 28 kts and believe most efficient for the boat to be at around 3600 rpm which is about 32 kts. (ish)

still wondering about changing the prop on ours but sometime i think better the devil you know... if we start playing with props is it the start of a slippery slope and maybe changing the way the boat handles which is mostly perfect for us!
Click to expand...

What diesel engines do you have with a rated speed of 4,500?
 
Props are very critical to best performance says he stating the obvious.

The manufacturers spend a lot of time getting the best out of the boat and so would have chosen a prop to give the best transfer of power to the water.

When I grounded our props a couple of years ago I was amazed at how critical this stuff is as the first dealer to 'fix' the props made a complete cods of the whole thing and in the end I had to go back to Sealine's original manufacturer and they fixed the pitch correctly. It has all been fine since although the wallet was considerably lighter at the time ;-0
 
100% agree - in fact I did mean to post in mine above that when SWMBO and I sea trial her at the factory that was on the 'second set' of props for the Princess. They then lifted her out again and fitted a 'third set'. The set fitted were the ones best suited in the opinion of the builder matched to the specific hull.....

I remain happy which their choice :-)
 
z1ppy said:
http://www.steyr-motors.com/marine/engines/6-cylinder-3200-cm3/

Steyr Mo256H45
Click to expand...

I know the Steyr 256 very well. Rated speed is 4,300 not 4,500 rpm. I cannot think of of a wose engine to overload. This engine needs to be propped LIGHT and you have to be able to see at least rated speed plus some droop clean and light. As this is an electronic engine droop is small.

Unless you can see at least 4,300 rpm WOT I can assure you engine will pick up a piston, two major operators have already been burned and remember the distributor is charging £14K for a long block. I am working with a yard in the Norh West who has a significant number of failed units and so far rebuilding has not proved successful, customer is insisting on 20 hour dyno test on rebuilt engines.

I keep banging on about propellers moving boats NOT the engines, and that your throttle is akin to cruise control in a vehicle, you set the rpm and the propeller tells the engine governor how much power is required which is with the exeption of rated speed, always less than the engines full load power curve. Hence shape of power curve Vs propeller demand curve.

If we turn this situation on its head and vessel is overpropped and you set throttle to maximum rpm (4,300) engine will be fuelling to achieve maximum power, however propeller is demanding more power than engine can provide and you are only making say 3,800 rpm or whatever rpm WOT gives, you are putting in fuel for maximum 4,300 rpm power with 3,800 rpm's worth of boost. Diesel engines must work on pricipal of excess air, without it cylinder temperatures go sky high. Going back to the comparison with cruise control on a vehicle, if you leave cruise in at too higher gear when pulling a grade the cruise kicks out when max engine load is reached. Marine engines do not have that feature.

Basic rules apply to ALL engines this is not a Volvo thing.
 
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aviator said:
Props are very critical to best performance says he stating the obvious.

The manufacturers spend a lot of time getting the best out of the boat and so would have chosen a prop to give the best transfer of power to the water.

When I grounded our props a couple of years ago I was amazed at how critical this stuff is as the first dealer to 'fix' the props made a complete cods of the whole thing and in the end I had to go back to Sealine's original manufacturer and they fixed the pitch correctly. It has all been fine since although the wallet was considerably lighter at the time ;-0
Click to expand...

Builders are not always the best people to decide what propeller match is best. Slide rule Sam in engineering often forgets that boats get harder to drive as they go though the season. The marketing people also want the best performance #'s for their data sheets.

Hinckley Yachts in the U.S. have been in dispute with Yanmar for well over a year now and there are plenty of others, Sealine boats with Cummins 370B shipped to U.S. were never propped correctly in line with Cummins installation guidelines and this was always a source of friction. Plain batty, as well as ill infomed builders/installers were such a problem that CMD completely re-wrote their installation guidelines in order that instructions were 200% clear, and they still get it wrong.

Always keep in mind the thread started by DAKA on what he saw as lack of durability/reliability of modern engiines.
 
Fred drifting

It always amazes me the number of people who will re engine spending thousands but want to save by keeping the old propeller because!xxxx

Funny how they don't get That changing the hp / speed doesn't require re propping
 
Latestarter, sorry to burden you with more silly questions but I have lived with my engines being able to over rev for 5 years now which you say has merits which I am happy to go along with but how do I know that I cant add another inch of pitch and still rev to max ?

Explanation

My engines were new when I got the boat and not run in.
Once run in they rev to 3950/4000

Rated @ 3800-3900 governor should cut in 3950 -/+ 25

I added an inch of pitch after season 1 and they still rev to 3950/4000

How do I know I cant add another inch of pitch ?

I have to say that they are incredibly economical, they appear very happy with current pitch, shall I add an inch or leave alone.


( Cummins-mercruiser 4.2 L D300, I know how much you love them, ;)
Nanni and MTU are now selling the VM706 )
 
DAKA said:
Latestarter, sorry to burden you with more silly questions but I have lived with my engines being able to over rev for 5 years now which you say has merits which I am happy to go along with but how do I know that I cant add another inch of pitch and still rev to max ?

Explanation

My engines were new when I got the boat and not run in.
Once run in they rev to 3950/4000

Rated @ 3800-3900 governor should cut in 3950 -/+ 25

I added an inch of pitch after season 1 and they still rev to 3950/4000

How do I know I cant add another inch of pitch ?

I have to say that they are incredibly economical, they appear very happy with current pitch, shall I add an inch or leave alone.


( Cummins-mercruiser 4.2 L D300, I know how much you love them, ;)
Nanni and MTU are now selling the VM706 )
Click to expand...

Very sensible question, these engines being quasi electronic have mechanical governor droop of around 10%, so you are pretty much on the money.

Personally I would invest in fitment of pyrometer. You can obtain good quality multi meters with pyro input for abaout £60. Make up K type thermocouple which you fit just after the turbo.

Take your vessel out for a trial well loaded and give it some 'tight wire'. If you are seeing around 350 C life is good and perhaps add some cupping. If you are knocking on the door of 400 C leave well alone, I think the VM maxes out at 410C.
 
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