boat hours

[chriscraft254]

Re: boat hours

Consider this when buying an older boat with an I/O, replacement with a rebuild is not that expensive. Then you will have 0 hours worst case. But like already said, hours really mean very little. Its how the boat is ran. The cruisers that you seem to be looking at usually are hangout boats. What I mean is that they are cruisers, one spot, hangout, move to another spot, hangout, dock, hangout etc, etc. These boats very rarely see wot speeds like some other go fast or sport fishing boats.

Condition, maintenance records, condition, maintenance records, condition, maintenance records!!! I agree that a properly maintained and run boat motor can last 2000 to 3000 hours easy. Its the ones that don't get used and are not maintained that fail pre-maturely.

I regularly put 200 plus hours of actual run time on my boat in a season. Good luck with your future purchase.

 

[Ned L]

Re: boat hours

UncleWillie got about as close as you can get. 'Traditionally' you look at boat engine hours as similar to a car running at 60mph (as has been said, boat engines work harder than car engines), so 800 hours of typical use would roughly equate to a car with 48,000 miles on it. Lots of life left if properly maintained. The big question to ask if the boat were around here would be is the engine fresh water or raw water cooled (salt water will rust out an engine regardless of the level of maintenance), however I see you are in UT, so I am assuming all fresh water lakes.

 

[Home Cookin']

Re: boat hours

maybe I/O's can't handle the hours but outboards can. and maybe it's different with I/O lake boaters, but few boats I know are run WOT most, or even much, of the time. It's a good question to ask you seller.

 

[H20Rat]

Re: boat hours

I don't even buy the 60 mph comparison... My car runs at between 7 and 10% throttle opening at 60 mph cruise. (yes, i actually do watch that, via a scangauge II) 10% throttle in a boat barely gets you moving. You spend far more time at 40-60% throttle opening. (60% throttle opening in my car is somewhere north of 120 mph)


Average boating is probably more like driving around at 100 mph all the time, from an engine perspective. Also, car engines have load changes, ie, going down hills. (obviously, your mileage will vary! Some vehicles might require your foot to floor and still not see 100 mph)

 

[Ned L]

Re: boat hours

Smokingcrater --- I would agree with you. I suppose I should have sort of 'updated' my comment. When I said "Traditionally" I was thinking 1960's & 70's technology before cars had overdrives & locking torque converters, and boats were run in the 2000 - 2500 RPM range for cruising.

 

[tpenfield]

Re: boat hours

One way that I look at the automotive versus marine comparison of engine wear and overall life is to base it on the fuel consumption.

Boats typically consume 8-10 times more than cars on a per mile or per hour basis. So, is an hour of marine engine life equal to about 8-10 hours of automotive life?

 

[Oshkosh1]

Re: boat hours

A comparison to piston pounding aircraft is more applicable here.

Miles are virtually irrelevent. Engines MUST be overhauled at certain TBO's(Time Between Overhaul) as the engine spends much of it's life at higher power settings/RPM'S/Manifold pressures than do their auto counterparts. Also, the consequences of engine failure due to fatigue are increased exponentially both on the water, and more so in the air.

 

[UncleWillie]

Re: boat hours

One way that I look at the automotive versus marine comparison of engine wear and overall life is to base it on the fuel consumption.

Boats typically consume 8-10 times more than cars on a per mile or per hour basis. So, is an hour of marine engine life equal to about 8-10 hours of automotive life?

You just may have something there!

Power over Time is Work. (In the engineering sense.)
And comparing Work to Work is comparing Apples to Apples!

My 4 cylinger car burns 2 gallons per hour at a 60 mph cruise.
A typical 4 cylinder boat burns 6 gallons per hour at cruise. (From BoatTest.com Test Results)
The Car is getting 30mpg and the Boat gets less than 6mpg, But that is not what we are comparing.

Giving a x3 (6/2) Conversion Factor of 180 miles per hour.
800 Boat Hours would be the equivalent of 144,000 Car Miles.
And 4800 gallons of fuel for each! (I don't even want to think about that part!)

This of course assumes that the Boat and Car each spent all 800 hour at Cruise speed.
So Smokingcrater's estimate of 100 mph may be more appropriate.
Which is again close to a x3 conversion factor of Car= 30mph average and Boat=100mph equivalent.
Making 800 Boat Hours be the equivalent of 80,000 Car Miles.
And around 2700 Gallons of fuel each.

As I said earlier, "Your Conversion Factor WILL Vary!"

 

[dingbat]

Re: boat hours

To make a comparison you would have to compare the operation profile (RPM, torque and the number and magnitude of load cycles per period) of a boat to an automobile. Keep in mind that the torque peaks, then drops out as the RPM increase. It also takes far less torque to keep an object in motion than it does to accelerate an object. Stop and go traffic, high/ low force cycles are far more destructive than running 70 MPH down a highway. How often do you boat in stop and go traffic?

BTW: the design life on an internal combustion engine for automobile us is 10,000 hours.

 

[tpenfield]

Re: boat hours

BTW: the design life on an internal combustion engine for automobile us is 10,000 hours.

That's what i was thinking as well . . . so (10,000 hours for an auto) /8 (fuel usage ratio) = 1,250 (hours for a boat).

 

[JimS123]

Re: boat hours

I've read what the pundits have had to say about I/O and OB life span. Believe it or not its up to you.

My own personal experience with an I/O is:

* 28 year old Mercruiser 3.0 140
* 1300 hours - i.e., ~45 hours a year
* cold weather climate - 6 month usage
* plugs, oil change, anti-freeze yearly, etc. - no other service EVER
* garage kept if not in the water.
* impeller, u-joint lube, etc. - all by the book
* Typical usage is at 3000 rpm (cruise speed)
* seldom run at WOT due to water conditions - when I do its only for a few minutes (don't need the speed - 35 mph is just fine!)
* compression, power, fuel usage - all like new

If she keeps running like this I'll get another 28 years out of her.

 

[26aftcab454]

Re: boat hours

a well maintained boat will have a owner who will talk your ear off telling you about his baby--and if he has records & recipts even better--ask specific questions about service . it should be fine!

 

[tpenfield]

Re: boat hours

So, back to the original question . . ."How many hours are considered high, I'm looking at a boat that has 800 hrs on it, is that too high of hrs or not?" Would it be a neutral, a negative or a positive?

I'm thinking it will be either neutral or negative . . . maybe slightly a negative, requiring further qualification in order to factor it into the value and purchase decision. The engine, with 800 hrs on it, may be more than 50% of the way through it's expected life and perhaps even closer to 80% of the way through, depending on its use and maintenance.

 

[Oshkosh1]

Re: boat hours

An oil analysis is also a good indication of specific internal part wear, water/coolant intrusion.

http://www.blackstone-labs.com/marine.php

They do a great job, and will answer any questions you may have...HIGHLY recommended.

 

[dingbat]

Re: boat hours

That's what i was thinking as well . . . so (10,000 hours for an auto) /8 (fuel usage ratio) = 1,250 (hours for a boat).

There is no relationship between the amount of fuel used and the life expectancy. Using your criteria a v4 would last twice as long as a v8 based upon your fuel usage ratio which we all know is silly.

To wear out a motor you eitherwear out the rings or the crank bearings. The rings are a cycle count. No way to calculate this other than to compare rpm profiles. The crank bearings would require a torque profile comparison to compare apples to apples. Unless you make these comparisons, you’re just pulling numbers out your butt.

Probably 99.9% of marine motors die from fuel related problems or water ingestion. I'm guessing not many cars die from water ingestion. How did you account for this phenomenon in your calculation?

 

[Home Cookin']

Re: boat hours

this is from a previous post, and compiled from another forum (tidalfish.com). These are all salt-water outboards, and many of the members are serious boaters. Sonmeone asked about motor age; folks replied; one guy with too much time on his hands compiled the responses. No, it's not scientific and it's anecdotal, but it gives you a sense. Note: the hours are not the hours when it died; it's the current age.
So 800 hrs is no concern for an outboard. Can't speak to I/O but if 800 is a problem, another reason to get an outboard.

Mfg Year Size Hours
Honda 2000 50 4826
Mercury 225 860
Mercury 1989 135 2200
Mercury 2001 150 3000
Mercury 2004 700
Mercury 2004 225 700
Mercury 2007 250 1150
Mercury 2006 135 175
Mercury 2009 225 580
Suzuki 250 4500
Suzuki 250 4500
Suzuki 1500
Suzuki 175 3000
Suzuki 175 3000
Suzuki 2003 115 3100
Suzuki 2003 115 3100
Suzuki 2006 150 1520
Suzuki 2006 225 600
Yamaha 250 1500
Yamaha 250 1500
Yamaha 2001 200 260
Yamaha 2002 225 900
Yamaha 2002 225 1200
Yamaha 2004 150 1900
Yamaha 2004 225 800
Yamaha 2006 150 800
Yamaha 2009 150 600
Yamaha 2006 150 9000
Yamaha 2006 250 2000
Yamaha 2009 150 765

 

[Oshkosh1]

Re: boat hours

So, back to the original question . . ."How many hours are considered high, I'm looking at a boat that has 800 hrs on it, is that too high of hrs or not?" Would it be a neutral, a negative or a positive?

THAT is the $64 question...and there really IS NO "correct" answer.

Too many variables/unknowns based upon individual knowledge, use/abuse and maintenance...or lack thereof.

All one can do is take into account the sum of all KNOWN and VERIFIABLE information based upon first hand non-destructive testing such as compression test, used oil analysis, "test drive" etc...not anecdotal assumptions, hearsay, hasty generalization, notions or pre-conceptions founded upon forum based impersonal opinion.

 

[UncleWillie]

Re: boat hours

There is no relationship between the amount of fuel used and the life expectancy. Using your criteria a v4 would last twice as long as a v8 based upon your fuel usage ratio which we all know is silly...

You need to Not lose the Apples to Apples comparison.
Don't compare Kia Miles to Aircraft Carrier hours!

Compare a 5L V8 Truck Engine to a 5L V8 Marine engine.

A 5L in a truck gets about 15 mpg and will long term average 30mph and burn ~2 Gal per hour . (Not Towing!)
A 5L in a boat burns about 7 Gal per hour at cruise. (Not WOT!)
So the boat burns 3.5 times more fuel in an hour with an equivalent engine, all other things being equal.

Given a x3.5 conversion factor.
1000 Hours x 3.5 x 30 mph = 105,000 miles

1000 Boat hours equals ~100,000 car miles, all other things being equal.
Or one Boat hour equal 100 car miles. (Funny, how that number keeps coming out of the math.)

Now, if the Truck is worn out at 50,000 miles or 250,000 miles depends a lot on the Owner.
If the Marine engine is worn out at 500 hours or 2500 hours also depends a lot on the Owner.

The "all other thing being equal" is the Wild Card!
The Wild card is the owner, the maintenance and how it was used.
And admittedly, it is a Very Big Wild Card!

Your conversion factor Will Vary!
The One Boat hour to 100 Car miles is about as close as you can figure within a factor of 2. (50 > 200)

 

[Home Cookin']

Re: boat hours

a-ha! you didn't factor in water temps and suspended solids.

 

[Philster]

Re: boat hours

Marinized for a V-hulled planing hull, life is rough if you're an engine:

• One gear. Sort of like riding your 12-speed bike in 12th gear all the time, but up a 45 degree hill, often trying to go as fast as possible. Your legs (engine) would be hurting.
• Extreme and persistent load (see manifold pressure comments above for indirect measurement of the load)
• >>A boat engine faces so much resistance that it can't propel a boat like the OP's example past 30-35. That is a massive am't of resistance the engine constantly works against.
• The exhaust system pushes water up and there is a chance that it can wick back into the engine.
• From sheer forces and fatigue, the one gear issue and the massive load the engine is under, and for a disproportionate amount of time versus a car engine, really puts the beat down on an engine.
  

At 800 hours, a compression check is nice, but a leakdown test is best.