Wide Open Throttle

S of S wrote;
“ So are you advocating not listening to his mechanics advice? He has trusted him for 20 plus years... Do you listen to Hattons advice or are you thinking they are trying to sell you parts on the engine you purchased? Hatton mechanics trying to rip you off?”

Not so.
All input is good. And if not at least it may be interesting. Listening to one’s mechanic is a very good thing and we listen to them more often that anyone.
But we can’t know too much re our engines and any imput adds to our knowledge or potential knowledge.
Add it all up, shuffle twice and consider all information. It’ll all add up to someth’in and knowing what info or source is best is very important. If you’re going to wash dishes listen to your mom .. not your bud down the street.

Hey Jack,
I just picked up on something. Initially I thought you were referring to Hatterass boats and their engine techs.
But from somewhere you remember my engine came from Hatton’s engines in Ballard (Seattle Wash). I’m sure impressed w your memory. Actually my engine came from Yukon engines .. under the same roof. And Yukon usta be Klassen. Hatton bought out Klassen and all their inventory. Soon after they changed their name to Yukon. Have no idea why.
Klassen is alive and well in southern BC Canada as far as I know. But in the USA Klassen products are available through Hatton Marine Engines.
Hatton offers some engines too big for trawlers.

Nomad Willy said:

Why are you overpropped Mark?
Trying to save a bit of fuel?.

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The boat was designed/built that way. I've no complaints.

Setting a boat up to increase the engine efficiency, lower the cruise RPM ., lower the noise and vibration on board and have the engine last longer is simply proper engineering.

Sure in theory it could be overproprd , asking the engine to handle a larger load than it was built for at a low rpm, tho it seldom is.

A 20% better fuel burn hardly matters to a boat burning 2-3 GPH , but operating the engine with good efficiency can extend the engine life as it operates with the load it was created to carry.

The hassle is props absorb way less power , even with slightly lower RPM , so an "overload" can be checked by simply advancing the throttle to see that 200-300 RPM more is available.

No question the surface skimming boats , like sport, fish that are usually run near wide open need to be sure the overload sign , black smoke , only is produced when accelerating , but for us displacement cruisers the HP required to cruise ia available at way lower RPM.

Its a totally different operating range for displacement cruisers, so the rules for pulling water skiers do not apply.

IF a cruiser had an engine closer to the HP required a WOT check would make sense , but with 30-40HP required and 120+ HP engines installed NOT seeing WOT RPM means some engineering and experience was used in the prop and tranny selection. A good thing.

FF said:

IF a cruiser had an engine closer to the HP required a WOT check would make sense , but with 30-40HP required and 120+ HP engines installed NOT seeing WOT RPM means some engineering and experience was used in the prop and tranny selection. A good thing.

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Or this could indicate problems such as barnacles on your prop, dirty fuel, fouled bottom, etc. I run my boat briefly to WOT everytime I take her out as a diagnostic to ensure all is well. My prop and transmission are set so I can achieve 3600 RPM in gear per Volvo. I recently was down about 200 RPM from just a few barnacles on my prop. It doesn't take much!

Most people never get their car or motorcycle to WOT
Not sure why you need to on your boat

Nomad Willy said:

Why are you overpropped Mark?
Trying to save a bit of fuel?

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If he can reach the rated 2400 RPM (even without a measurable increase in boat speed), I'd say he's not overpropped, he's just a little overpowered.

Simi 60 said:

Most people never get their car or motorcycle to WOT
Not sure why you need to on your boat

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Was thinking along that basis the other day; boat - vs - road vehicle WOT tests.

I realized... you can't [most likely won't] run road vehicles at WOT for any period of time, unless you gear down and hold engine at WOT RPM.

Would be pretty silly spending 3 minutes or more rolling down the HWY at 60 mph in 2nd or 3rd gear with engine at WOT; just for the sake of being at WOT to test if engine could do it. Of course you could do WOT in top gear... usually at well over 100 mph.

Now; some road vehicles do reach pretty high rpm [basically WOT range] during upshifts... but... that high rpm is reached only for split second.

Where as boats are a different animal. Boat engines are geared differently, with different load factors and vastly differently top end speeds [well, most boats are anyway]. So... in a boat it's [usually] not to difficult to go WOT for a multi minute period of time; if desired. And, I do believe in using WOT for a limited time-span on boats for occasional mechanical/heat check ups as well as to be used when there is need to immediately alter a position regarding the water's surroundings. What I don't understand is doing WOT very often; just for the heck of it. Not saying that often using the limited time-span WOT technique is incorrect to do... just don't understand why to bother doing that???

Professional Boatbuilder has a good write-up on the subject:
https://www.proboat.com/2010/09/wide-open-throttle/

Most boaters underwork their diesels as it is and are afraid of pushing their diesel to WOT, but it is a good diagnostic tool. If a diesel self-destructs while briefly at WOT than there was a major preexisting problem.

And.... big deal?


If your engine works happily along at your normal operating rpm for thousands of hours and you do due diligence maintenance.... finding out there is a problem at WOT gives you what? It doesn't like WOT?


I have had an annoying head gasket compression leak into the coolant system for at least 2500 hrs and nearly 15000 miles. Why should I push a Lehman that some say hate WOT versus lower RPMs and chance a bigger problem than cruising along at 1600 RPM and living happily for anther 2000 hours?


I love technical versus reality discussions....


A lot of people make a lot of money discussing "a perfect situation"....some of us just go thru life operating in a less than perfect world and prove theory or "perfect world" is just that.

The idea isn't to go WOT often or for very long. So you're not beating on it. The idea is to see if WOT now behaves differently than WOT a year ago. If it's the same, all is good. if it's 200 RPM less, smoky and has some extra vibration, well, something is wrong. Might be an engine issue or might be crud on the prop or prop damage, but either way, it's likely affecting things at cruise speed, just not as obviously. And depending on what it is, it may get worse.

Catching a problem while it's minor and can be fixed on your terms is always better than waiting until the problem says "ok, I'm here, fix me now!"

psneeld said:

A lot of people make a lot of money discussing "a perfect situation"....some of us just go thru life operating in a less than perfect world and prove theory or "perfect world" is just that.

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I will agree with you on that! My wife constantly reminds me to enjoy the boat rather than obsess over mechanical and cosmetic issues!

Now, I have been in a situation where I needed almost every HP from my little 29HP Volvo. Knowing that I could push my engine to near WOT without a mechanical issue was assuring and may have kept my boat from being grounded. Emergencies do happen--I try to avoid them--but they do happen.

Seriously? Why do people think every poster is a newbie?


I get all that...I am way beyond you....OK so I go to WOT and I get a slight rise in coolant temp...ot I don't get to WOT because the previous owner was smart enough to realize the boat was going to run well at 6.5 knots...not 7 or 8.


Big deal...I would rather take the chance of not doing further damage to the head gasket and run below 1800 RPM and run another 20,000 miles before I need to do something.


It's not going to change my cruising habits one bit.


I just don't but into the Kool Aid theory that I am protecting myself when I know how to handle what I have.


If I did...I might have overreacted 15000 miles ago.


If I have an emergency...I probably will get enough fot those few moments I need full throttle...if the engine goes then or overheats...so be it. But running boats commercially as log as I have...rarely is full throttle the answer to anything.

rslifkin said:

Catching a problem while it's minor and can be fixed on your terms is always better than waiting until the problem says "ok, I'm here, fix me now!"

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Well said!

Bringing it home, when I bought it, just to see what the top speed really was, and to make sure it was propped right.

I've never had another reason to run WOT since.

rslifkin said:

If he can reach the rated 2400 RPM (even without a measurable increase in boat speed), I'd say he's not overpropped, he's just a little overpowered.

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He can’t. He states top speed as at 2200.
How’ed he get max speed at 2200 if he wasn’t overpropped?

Actually Marks boat probably isn’t overpowered. His Coot must weigh twice as much as my Willard and my Willard only has 37hp.

If Mark states his displacement we would know for sure.

Nomad Willy said:

He can’t. He states top speed as at 2200.
How’ed he get max speed at 2200 if he wasn’t overpropped?

Actually Marks boat probably isn’t overpowered. His Coot must weigh twice as much as my Willard and my Willard only has 37hp.

If Mark states his displacement we would know for sure.

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The way he phrased his comment made me think that 2200 was enough to get the boat to top speed and pushing it further to 2400 just burned more fuel without going faster (rather than engine rated for 2400 but can only reach 2200).

markpierce said:

The boat was designed/built that way. I've no complaints.

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Would be interesting to hear what JD thinks about that.

Vashon_Trawler said:

Well said!

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For a person constantly moving...not necessarily the best answer and for most of the issues..they were either routing maintenance or constant vigilance would signal the issue without ever going to WOT....


at least in my experience.

psneeld said:

For a person constantly moving...not necessarily the best answer and for most of the issues..they were either routing maintenance or constant vigilance would signal the issue without ever going to WOT....


at least in my experience.

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For a lot of issues, yes. For me, an early season WOT check is mostly for 2 things: props performing as expected? Cooling system working well enough to handle normal cruising loads once the water gets warmer?

A WOT check later in the season is primarily to confirm that the props are still clean and proper.

Outside of those 2 or so checks during the season, I'm one of those who will never push the throttles past normal cruise without a very good reason. Not worth the extra engine wear just to go a little faster.

rslifkin said:

The way he phrased his comment made me think that 2200 was enough to get the boat to top speed and pushing it further to 2400 just burned more fuel without going faster (rather than engine rated for 2400 but can only reach 2200).

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I see your thinking but top speed can always be upped w a bit more power and rpm. And top speed would be the speed reached at WOT if that produced rated rpm. At 2200rpm Mark’s JD is not producing max power .. and thus won’t be at max speed.

On a displacement hull, wouldn't you potentially hit a point where another bit of RPM and power comes in the form of the boat pushing a bit more water, maybe going 0.1 kt faster (potentially within measuring error) and experiencing more prop slip?

rslifkin said:

For a lot of issues, yes. For me, an early season WOT check is mostly for 2 things: props performing as expected? Cooling system working well enough to handle normal cruising loads once the water gets warmer?

A WOT check later in the season is primarily to confirm that the props are still clean and proper.

Outside of those 2 or so checks during the season, I'm one of those who will never push the throttles past normal cruise without a very good reason. Not worth the extra engine wear just to go a little faster.

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Wow...if I didn't know the condition of my bottom or cooling system without a WOT test all year long....well I wouldn't say it to be polite.


And it keeps me from a major maintenance action maybe when I don't want it.

psneeld said:

Wow...if I didn't know the condition of my bottom or cooling system without a WOT test all year long....well I wouldn't say it to be polite.

And it keeps me from a major maintenance action maybe when I don't want it.

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I usually have a pretty good idea of both, but it's a good confirmation that I haven't missed anything. Then again, I'm usually of the opinion with engines (in boats, cars, etc.) that if I'm going to break it by going WOT for 30 seconds or a minute, it was probably already broken.

rslifkin said:

I usually have a pretty good idea of both, but it's a good confirmation that I haven't missed anything. Then again, I'm usually of the opinion with engines (in boats, cars, etc.) that if I'm going to break it by going WOT for 30 seconds or a minute, it was probably already broken.

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Thousands of hours more experience and you might change your mind....some of us have been running broken boats (according to magazine and TF opinion) for much of our professional lives.


Sometimes nursing along sick equipment is OK...as long as you know it's limitations and reduce risks where max performance is necessary (outside of a few situations...rarely necessary)

psneeld said:

Thousands of hours more experience and you might change your mind....some of us have been running broken boats (according to magazine and TF opinion) for much of our professional lives.


Sometimes nursing along sick equipment is OK...as long as you know it's limitations and reduce risks where max performance is necessary (outside of a few situations...rarely necessary)

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You have me curious. What kind of head gasket problem do you have that WOT would mean immediate work needed but 5,000 engine hours may not.

I am guessing at your boat speed of 7 knots and using your stated 15,000 miles to date and another 20,000 miles before you will address it.
I did not think a known head gasket issue would last that long.

Soo-Valley said:

You have me curious. What kind of head gasket problem do you have that WOT would mean immediate work needed but 5,000 engine hours may not.

I am guessing at your boat speed of 7 knots and using your stated 15,000 miles to date and another 20,000 miles before you will address it.
I did not think a known head gasket issue would last that long.

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I have a tiny bubble stream in my coolant putting either oily soot or oil in my coolant.


It was there for maybe a couple thousand hours before I noticed it...put a new head gasket in that only lasted 100 hours and added another 1500 hours with it bubbling.


You are correct that WOT may or may not do anything...but why chance it because it is not hampering my cruising as of now?


Boat speed is usually 6-6.5 at best.

In your case I'd agree with not going WOT until you're ready to figure out a permanent fix for the issue. In that situation, there's a known issue that's being worked with and more stress may make it worse.

psneeld said:

I have a tiny bubble stream in my coolant putting either oily soot or oil in my coolant.


It was there for maybe a couple thousand hours before I noticed it...put a new head gasket in that only lasted 100 hours and added another 1500 hours with it bubbling.


You are correct that WOT may or may not do anything...but why chance it because it is not hampering my cruising as of now?

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I remember the other thread now. If I did not say it there, may I suggest it is an exhaust manifold gasket leak, or worse the manifold itself. You replaced the head gasket because of that problem IIRC.

It's also possible the head or block is just slightly warped, which caused the new head gasket to fail. If that's the case, machine shop work would be the only fix.

rslifkin said:

It's also possible the head or block is just slightly warped, which caused the new head gasket to fail. If that's the case, machine shop work would be the only fix.

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Maybe, but less likely. any warpage would have blown out the head gasket by now as it would not be fully seated