Young(ish) boat/high engine hours?

[Blue Sunray]

I'm currently considering a boat that is less than six years old but has just under 1500 hours on the engine (Volvo) - I believe that this is due to it having been used mostly touring inland waterways at low speeds (though it is a Cat B vessel). I would be using her offshore.

I've searched around the forum and found some commentary on, for example, the possibly of bore glazing though extended use at low speeds. I would be grateful for the forum's thoughts on the risks involved in taking such a boat on.

 

[Chris_d]

I've heard lots of "experts" talk about bore glazing, but I have yet to meet anybody who has suffered from it or heard of it costing anybody anything in having rebores, new pistons etc... There are thousands of over engined offshore boats potting up and down the Thames and other waterways including my own.
Try doing a search for "bore glazing" and I reckon there are lots of warnings about it but nobody asking how to fix it. Bit of a myth is my conclusion after 30 years of not suffering from it.

 

[kashurst]

1500 hours is not a lot for an engine, however it is often perceived as a lot for a boat engine. The good side of this is that the boat price should reflect the higher hours compared to a low hours (unused) equivalent. I bought my curent boat with just over a 1000 hours on a 6 year old boat. The price differential between that boat and the nearest in price/condiction was more than the cost of a full rebuild or a secondhand engine should something go wrong. So I decided it was worth the risk. I did recently have a few issues but they were not wear/age related. Boat engines fail usually through lack of use as the marine add ons (intercoolers etc) get gunged up and no longer protect the core diesel engine as well as they are supposed to. An engine that has been used regularly will almost certainly be in better condition internally than one thats done 20 hours a year, and spent most of its life festering in a marina. Bore glazing is unlikely - I think its a bit of a myth (wait to be shot down). If the engine is creating blue smoke from the exhaust it may be bore glazing or it could be valve stem seals or piston ring damage/wear. However modern engines are less susceptible to it and the valve seals designs are better too. What make of boat/engine are you considering?

 

[Nick_H]

There's an interesting article here from Vyv Cox, who seems to be highly respected on here and elsewhere.

https://coxengineering.sharepoint.com/Pages/Boreglazing.aspx

I think this bit is most relevant:

"bore polishing is always a possibility with light loading. The solution is always to load the engine when battery charging, by driving the propeller. An engine that is driving the boat will never suffer from either glazing or polishing, even if it is at anchor or on a mooring "

He does also say that the first 100 hours are most important, and it's best to work the engine more during this period. Was the boat always on the river?

 

[Deleted User YDKXO]

I once bought a 2ndhand Fairline Turbo 36 which the 1st owner had kept on the Thames for several years and ventured out into the estuary once a year for his holiday cruise. I was concerned about the same thing ie bore glazing but in 3 yrs of our ownership during which we used the boat for offshore cruising I never had any engine issues except that both engines leaked oil quite a lot. The service company that I used at the time put this down to the fact that the oil seals had become hardened during their years of under use on the Thames and when put under stress during my ownership, they couldn't provide a proper seal. The leaks were never bad enough to warrant replacing the seals but I did go through a lot of bilge cleaner

 

[sia20]

just bought boat 1000 hours 7 years old vp d4s I ask the same question nearly everybody I spoke to about it ie Volvo dealers mechanics surveyers brokers ect said as long as it has a good service history they would rather buy it than boat with low hours sat all its life in marina and hardly used

 

[mlines]

Once watched a large Broom on the Thames (who thought no-one was looking) ram the throttles forward. He promptly disappeared in a cloud of white smoke that a Royal Navy destroyer would have been proud of as a smokescreen. Caught up with him around the corner to see him reversing in a circle at some speed!.

Not only had the engines kicked out years of crud through the exhausts but the action had pulled the throttle cables off the engines leaving him with no engine at all on one side and an engine that would only go into reverse and only at high revs on the other.

The main stories I have heard is of reliability issues once at sea. Gentle cruising on the river has rattled parts loose but never really shaken them. Hitting the sea causes the bits to fall off, disconnect etc and all the crud in the fuel tanks and water tanks to be shaken around.

 

[Momac]

I keep my boat on the R Trent. We do a good deal of speed restricted slow speed travel with occasional trips that allow the intended performance of the boat.
The engine may well become a bit sluggish and smokey with prolonged slow speed use . A bit of a thrashing or preferably a good fast run now and again seems sufficient to keeps things like turbo's working as they should. A fuel additive helps. So I woudn't be too concerned but would suggest it important to see the boat will achieve reasonably fast speed during the survey.

Even though used at river speed the oil change at 100 hours remains important . So ask for some evidence of service history.
.

 

[Nick_H]

Even though used at river speed the oil change at 100 hours remains important .

Why is that? I'd have thought at lower RPM the oil is doing less work and therefore will last for more running hours? Did the boat really need an oil change mid season each year when it's only pottering about on the river at probably 800 RPM?

 

[Portofino]

Why is that? I'd have thought at lower RPM the oil is doing less work and therefore will last for more running hours? Did the boat really need an oil change mid season each year when it's only pottering about on the river at probably 800 RPM?

I think it's more of a case of diluting toxic acids that attack the metal surfaces , the main reason .Thats why it's suggested oil change before any winter lay up period or annually if low hours .

Rarther than a lube /viscosity issue of a bashed oil after 1000hrs or so in a season .
Of course chucking away less than 100 hrs oil does not seem right .

 

[Spi D]

Diesel or petrol engine, sea water or fresh water cooled?

No engine is designed not to work so endless hours of idling is not optimal. They are designed to work and benefit from being allowed to do so.
A fresh water cooled diesel that has been serviced is barely run in at 1000 hours. Goes without saying that service and maintenance is key.

 

[GSL]

Interesting
3 years ago I bought a boat that had been in a dealers stock for 4 years, in the water and had the engines warmed every week or two.

The records showed the the engines put on 65 hours in those 4 years, and no one I spoke to could remember the boat going to sea more than the once in those 4 years, it was used for a staff party.

I bought the boat (it was very well priced) took oil samples before changing all oils before the 420 mile trip back to home port.

The samples showed zero problems, and touch wood, the engines have been fine ever since.

Four full seasons and very low rpm warm ups did not seem to have any negative effect.

Graham

 

[Nick_H]

I think it's more of a case of diluting toxic acids that attack the metal surfaces , the main reason .Thats why it's suggested oil change before any winter lay up period or annually if low hours .

Rarther than a lube /viscosity issue of a bashed oil after 1000hrs or so in a season .
Of course chucking away less than 100 hrs oil does not seem right .

I get that, but MartynG was suggesting oil should be changed 2-3 times a year for the boat referred to in the OP, even though at each change the engine would have done the same number of cycles as it would in just 25 hours at normal cruising speed. It seems a bit OTT, but I was interested to hear his reasons as I do a lot of cruising at low RPM.

 

[Momac]

Why is that? I'd have thought at lower RPM the oil is doing less work and therefore will last for more running hours? Did the boat really need an oil change mid season each year when it's only pottering about on the river at probably 800 RPM?

The recommended oil change interval (for my engines - kad32)is 100 hours.
I feel the oil may well attract the same if not more contamination from running slow as it does from running fast. when running slow the full running temperature is only just achieved which I feel also is making he oil work harder.
I change my oil once year - which for me, on average, has been about 100 engine hours although I am not fussy about the precise number of hours - for example this year have done 120 hours.
.