Engine Hours

[sab30]

I am aware hours vary widely depending on your use but is there a rule of thumb for engine hours on a boat per year..ie avg 50-100-200. As with a vehicle they say an avg is about 20,000 miles per year as a barometer...what about for sailboats?

[NOLAsailing]

In my experience, it varies quite wildly. However, most sailboat engines, particularly quality diesels, can have extremely long service lives if they are properly and meticulously maintained. The better question is whether or not any service records exist.

Also, ask how the owner used the motor. If he just ran it in the slip to charge the batteries occasionally, it might be a red flag. If he ran it under load, ask what he uses as his cruising RPM - it should be about 80% of the max RPM.

When I was shopping for a boat, the sellers and brokers rarely knew the hours - either because they did not want to share, the hour meter was broken, or the motor did not have an hour meter.

When inspecting the motor, look for signs of corrosion, particularly near the water pump, heat exchanger, and oil pan. Also look for oil leaks, poor wiring, and old hoses. All should be indicators of a less than perfectly maintained motor.

Also, if you get the point where you can run the motor - look for smoke. Smoke that persists after startup can be indicative of a number of problems. Another thing to look for is power output. If a motor cannot generate it's rated RPM, then there is an issue. It might be as simple as an improperly sized prop, but more likely indicates something more seriously wrong with the motor.

If the motor runs well, doesn't smoke, produces its rates RPM and operates at a proper temperature, then it is probably OK.

I don't mean to suggest that engine hours aren't important - they are. However, in a purchase scenario the factors listed above significantly outweigh the usage.

If you're asking for a personal reason - to see if your a high mileage driver for instance - don't worry about it. Keep track of the hours for maintenance and use the heck out of it.

[sab30]

Thanks Nola..I am currently looking at a couple boats narrowed down to offer. I was just curious because one is a 2004 with 150 hours..didnt seem like much as even in charters we have put on 10 hrs on a weekend. I was expecting 300-500 for a 4 year old boat.

[k1vsk]

There are only two things which are not good practice for maintaining a marine diesel - too little use and too much no-load use. An engine sitting idle for prolonged periods is, as you can image, not good. Running at idle for prolonged periods with no load, such as at anchor, also damages the engine - not as obvious as a low hours engine I know. If it has been properly used and maintained, they can run wellfor thousands of hours before a major overhaul is needed. The only way to ensure you know what you're buying is to have a marine diesel mechanic survey the engine at the same time the boat surveyor is doing his thing

[Rockter]

Not an easy call.
Does it use oil?
Is the exhaust smoky?
Does it start readily from cold?

[sailaway21]

sab,
I cannot agree more with NOLAsailing. The problem with diesels on sailboats is that they often do not get warmed up enough during their short usage and, a related problem, do not get their oil changed enough. On a normally used diesel I'd say that the 1000 hour mark is the beginning of middle age, requiring more maintenance. Given the way many are used though, this may occur much earlier in a marine diesel. His suggestions on other factors of evaluation are more important than mere hours.

If you are not familiar with diesel engines, k1vsk's suggestion of having a mechanic look it over is not only sensible, but should be mandatory. Remember you will not only be rebuilding the engine, which may be straight forward, you will be removing and re-installing it in the boat which could be "interesting".

[Rockter]

I would be less daunted by taking the motor out of a sailboat than I would be by having to re-engine with different mounts and alignment. The former is about 1/2 hr with a wee crane : the latter is awful.

Taking the motor out is not normally too bad. I would not use the boom though. Mine really needed a crane.... it was too heavy.

Continuous running really doesn't bother them much. Long continuous running hours are not that rare in a sailboat. Often we have calms, and have to motor and motor.

Even if it just had the oil changes regularly, it will probably be ok, but it is not an easy call.

Excessive smoke is probably the clearest warning. I have always found it difficult to separate the blue/white smoke of a worn bore on a hot engine from the white of the steam, so testing for bore wear will be in the opening seconds of running under load (not strictly a good test), or on one occasion I shut the water off for a WEE while to clear the steam a little. It's risky though. I had to take the water pump off the motor.... all very awkward stuff.

Some engineers stick their hand into the exhaust spray of the hot engine to see how much filth is coming out.

Ideally it would have to be run for a number of hours to see how much oil it is using. Mine ate a pint every 7 (or so) hours when I bought it. I found that out crossing the Gulf of Mexico in unbelievable calms and fierce sun. I nearly ran out of oil... not fuel.

Good luck anyway.

[sab30]

Thanks to all I am in the final selection of a boat..trust me no hurry there is GLOBS of inventory out there at some very reasonable pricing. I wasnt aware of the diesel survey but I will make sure it is included when I survey the boat.

[CalypsoP35]

Originally Posted by sab30

Thanks Nola..I am currently looking at a couple boats narrowed down to offer. I was just curious because one is a 2004 with 150 hours..didnt seem like much as even in charters we have put on 10 hrs on a weekend. I was expecting 300-500 for a 4 year old boat.

Sab30, 10 hours on a weekend?? Are we talking sailboats or power boats here? Last year I think I had one day where I powered into the wind for 5 hours because the family was anxious to get to our destination and one day where I powered 4 hours because of lack of wind. Other than that I probably average 1.5 to 2 hours a week powering in and out the harbor. This year I have not powered at all except for powering in and out of the harbor.

[Valiente]

My game plan for long-term cruising and energy generation at anchor is predicated partly on a desire to avoid running the engine just to spin the alternator (bad) and an acknowledgement that a once-a-week run of six hours at 2,100 RPM or so is likely a better policy than 10 minutes of 1,500 RPM getting in and out of a slip.

Diesels, to my understanding, are essentially opposite to gasoline engines in terms of compression, tolerances, and patterns of wear versus usage. Owning an Atomic 4 meant I could run it for the typical 10 minutes until I got the main up, and the fact that it never got above 120 F would make no difference. The starter would wear out quicker, I suppose. This is why a gas auxiliary makes sense on a sailboat.

I now have a diesel in a motor sailer/"sailer-motor". I STILL don't need to run the engine a lot, but I accept that having it spinning the prop at low revs (light load) for an hour or so during sailing is better for the lubrication and the general stress on the moving parts (which want heated oil on them) than would be the case were I to "turn on and shut off". Diesels, like athletes in a marathon, need warming up for the long hauls.

So if I want to keep the engine off in order to avoid charging at anchor with a "stationary" diesel, I have to have wind power, solar power, and a backup genset. I also have to be willing to "take the old girl out" for an extended run on occasion in order to keep all parts lubed and mobile.

In return, I hope to get the benefits of a reliable and fuel-stingy diesel able to run for several days in a row when needed, and I hope to avoid the frankly stupid habit of running the thing at anchor in order to keep the beer cold.

Frankly, when they get diesel-electric systems bulletproof enough for 40 footers, I suspect I would be an early adapter, because I can handle both the weight of the batteries plus the utility of a diesel genset that turns not a shaft in water, but magnets on a shaft at a constant speed. Seems a better use of the technology in the long run. Until then...