Engines: Old and easy to repair vs New and reliable.

[GoneDiving]

Originally Posted by Simi 60

Don't get me wrong, Gardner's are a great motor but if travelling remote I would prefer engines where parts and service can be found almost anywhere.

Why hasn't Cat been mentioned during the generic, easy to find discussions? Every industrial park has many of them lying around and the same base engine can be found in highway trucks, generators, graders, water pumps world wide.

Why haven't they been popular for marine usage?

[GoneDiving]

Originally Posted by Bundyon

No common rail for me, am running a little 4-236 Perkins 80h.p. pushing 24 ton at around 6knots @ 1500rpm for about 3.5 li/hr.
I run a Racor for a primary filter & a C.A.V. 796 for a secondary filter. After getting down lower than normal on fuel and in 5 metre seas and having heavily dosed my fuel tank with fuel doctor, I came into a safe anchorage after crossing a Bar with black smoke chuffing out the exhaust.
A much needed filter change, the Racor bowl was full of sludge, both filters full of "black death". The Perkins never missed a beat, I could only imagine a common rail engine would have left me stranded in big seas.

I've been amazed at some of the fuel usage numbers for tiny engines pushing full size boats. I'm sure there is some seller exaggeration but they are impressive non the less.

Have there been any times where your low output has been an issue?

Thanks

[GoneDiving]

Originally Posted by Simi 60

Even on engines where they don't get worked hard?

On ours, I don't hear the turbo spinning up until we get up around 1500rpm of her 1800 max, but that does little more than burn excessive fuel and only gets done occasionally to blow out the cobwebs.



99.9% of the time we do miles in the 1150 to 1250 rpm range for 8 knots.
Would the turbo be doing anything?

The Asian truck engine swaps I mentioned earlier mostly have their turbos removed and converted to NA. I was told it improves fuel usage and reduces engine bay temps.

Keep in mind I'm talking super low tech, fencing wire conversions.

Cheers

[GoneDiving]

Originally Posted by Tillsbury

I agree to avoid common rail and electronically controlled engines, but I don't think turbos are a worry. They're a very simple part, they can easily be replaced or rebuilt if you need to, and the engine will still work even if the turbo is hopelessly shot and rusted solid.

I dont see turbos per se as a major negative esp on a cruiser that has extended run times rather than repeated cold starts.

What I'm not in favour of is turbos being used to push even more power out of highly strung small blocks. But these aren't part of the discussion here

Thanks

Cheers

[Compass790]

Originally Posted by GoneDiving

Why hasn't Cat been mentioned during the generic, easy to find discussions? Every industrial park has many of them lying around and the same base engine can be found in highway trucks, generators, graders, water pumps world wide.

Why haven't they been popular for marine usage?

I worked on a 64ft steel schooner ( really a motorsailer ) that had a 75hp CAT. It was over 50 ton & had a Hundestat variable pitch prop.
Owner was a retired marine surveyor & mechanical engineer, he probably marinised it himself. ( can't remember it was in the 90's & 2000) He loved that engine & the setup was perfect for extended range as with the EGT monitoring & the variable pitch prop you could set it up for the most economical fuel burn.
Zero problems with the motor except when its air filter got clogged by an exhaust leak from the generator, can't blame CAT for that.
Cant remember how many hours it did but I'd say a CAT would be fine for what you want as long as you size the hx & raw water/coolant pumps properly

[skipperpete]

Originally Posted by GoneDiving

Why hasn't Cat been mentioned during the generic, easy to find discussions? Every industrial park has many of them lying around and the same base engine can be found in highway trucks, generators, graders, water pumps world wide.



Why haven't they been popular for marine usage?

Caterpillar are very expensive initially and the parts prices are extreme but availability is superb. Most of the Cat range is at the higher end regarding horsepower and the marine range market is either superyachts or commercial vessels. They don’t really cater to the cruising yacht community apart from the 3208 model which was popular in trawler type designs and occasionally sailboats. Recent small Cat engines in generators and skid steer loaders are Shibaura......now Cat mechanics need metric wrenches.
Up to 350 hp the engines I like are Cummins 855, large frame Yanmar, John Deere and probably DetroitDiesel but the EPA has put a roadblock in front of most of these engines in the “non common rail” models. Gardner’s are lovely old engines, I had a 5LW swinging a 36” Hundested CPP in my first boat, the engine was out of an old crane and cost me Au$400...... the Hundested was $10,000 with reduction gear.
The Gardner guys in Ireland flew to here some years ago and fully overhauled an 8LXB in a yacht at considerable expense, sadly it only did a few hours before being seized by the Malaysian police for having undeclared firearms aboard and is still languishing in custody at the police dock. Still possible to buy Gardner engines in Bangkok and Hongkong but the power/weight ratio makes them difficult to justify......an 8L3B actually takes an appreciable amount of time just to walk around.

[Lepke]

Originally Posted by Simi 60

Even on engines where they don't get worked hard?
99.9% of the time we do miles in the 1150 to 1250 rpm range for 8 knots.
Would the turbo be doing anything?

Yes even on engines that don't work as hard.
The turbo spins all the time, just not as fast. The shaft is turning, the seals rubbing, bearings wearing and it's constantly exposed to 500°+.
With engines where I've run both naturals and turbo, Detroit and Cummings, at least 3x. And I baby my turbo engines and run clean oil. Naturals I run at max continuous.

[GoneDiving]

Originally Posted by Lepke

With engines where I've run both naturals and turbo, Detroit and Cummings, at least 3x. And I baby my turbo engines and run clean oil. Naturals I run at max continuous.

I agree with your reasoning but also see my earlier comments re output per cubic inch. Again using the 671 as the extreme case, they go from 170hp to 300 in various stages by adding turbo(s), coolers etc. Its not surprising that the NA 671 is regarded as bullet proof and long lasting where as the higher output models are not.

Cheers

[rslifkin]

Originally Posted by GoneDiving

I agree with your reasoning but also see my earlier comments re output per cubic inch. Again using the 671 as the extreme case, they go from 170hp to 300 in various stages by adding turbo(s), coolers etc. Its not surprising that the NA 671 is regarded as bullet proof and long lasting where as the higher output models are not.

Cheers

I'll agree. It's not so much about turbo or non, etc. It's more about every engine design has a given range of power output and cruising RPM where it'll live a good, long life. Turn the power up too much or run it too hard and life gets shorter.

Turning the power up too much for a design can hurt lifespan even if it's never run hard. With more power, the engine ends up with bigger props to load it, so it has to make cruise power at lower RPM. Beyond a point, that starts to be hard on various components.

[mvweebles]

[QUOTE=GoneDiving;3073981]I've been amazed at some of the fuel usage numbers for tiny engines pushing full size boats. I'm sure there is some seller exaggeration but they are impressive non the less. QUOTE]

Agree about owner-exaggeration on fuel economy. Delivery Skippers learn quickly to take with a grain of salt - not that owners are necessarily purposeful in their exaggeration, but that their use of the boat includes idling, slow-speed, etc. and skews low.

That said, the Willard Boat Owner's archive includes a 1987 letter from an owner of a Willard 36 with a Perkins 4.236 that took his boat from San Diego to Hawaii. He burned 330 gallons of diesel over 15-days and averaged about 6-1/2 kts. Works out to around 0.9 gph. I found an old sales' video of the boat on YouTube (link below if interested - not a video of the trip, but there is mention of it - again, WBO archives have the actual letter documenting the trip so not taking broker's word for it) different deck house config, but same Wm Garden designed hull and propulsion. While my sedan version carries almost 500g of diesel, this pilothouse version only carries 300g so this the owner lashed barrels into the cockpit. I'm pretty sure his numbers were accurate as there was undoubtedly a point of no-return moment where they had to decide if they had sufficient fuel.

https://www.youtube.com/watch?v=0KNpJrXtKUs

[skipmac]

Originally Posted by Pauls

The old 2 stroke GMs have much worse fuel economy than a 4 stroke. I do disagree that the electronic controlled engines are significantly more fuel efficient than a good mechanically injected engine FOR MARINE USE. Electronics allows a lot of complex injection control which benefits cars and trucks that are constantly changing throttle, speed, idling, etc. They can achieve lower emissions levels for these vehicles. Constant RPM under a load is a much simpler condition. There are very good modern diesels available with mechanical injection that are very efficient. I have a 3.3L Cummins, all mechanical, which is highly efficient and easy to work on.

I was wondering if someone was going to mention the fact that 6-71s are two stroke engines. That is a significant factor in their poor fuel economy and as you mention, going four stroke even if not common rail or electronically controlled will give you much better economy and range.

[GoneDiving]

[QUOTE=mvweebles;3074280]

Originally Posted by GoneDiving

I've been amazed at some of the fuel usage numbers for tiny engines pushing full size boats. I'm sure there is some seller exaggeration but they are impressive non the less. QUOTE]

Agree about owner-exaggeration on fuel economy. Delivery Skippers learn quickly to take with a grain of salt - not that owners are necessarily purposeful in their exaggeration, but that their use of the boat includes idling, slow-speed, etc. and skews low.

That said, the Willard Boat Owner's archive includes a 1987 letter from an owner of a Willard 36 with a Perkins 4.236 that took his boat from San Diego to Hawaii. He burned 330 gallons of diesel over 15-days and averaged about 6-1/2 kts. Works out to around 0.9 gph. I found an old sales' video of the boat on YouTube (link below if interested - not a video of the trip, but there is mention of it - again, WBO archives have the actual letter documenting the trip so not taking broker's word for it) different deck house config, but same Wm Garden designed hull and propulsion. While my sedan version carries almost 500g of diesel, this pilothouse version only carries 300g so this the owner lashed barrels into the cockpit. I'm pretty sure his numbers were accurate as there was undoubtedly a point of no-return moment where they had to decide if they had sufficient fuel.

Thanks for that. Very informative.

So what's the down side to having a low powered cruiser (say <100hp in a 25t 50 footer) in which the captain has no intention of exceeding say 7 knots:

Not maintaining forward passage in strong currents (wait it out)?
Insufficient power in rough seas?

What have I missed?

[AKA-None]

Why is it either or? Are there no reliable yet easy to repair engines out there?

[Wotname]

Originally Posted by Simi 60

......

Those same parts for our 855 would be on a plane from Cummins China and here inside a week, rebuild probably could have been done anywhere.

Don't get me wrong, Gardner's are a great motor but if travelling remote I would prefer engines where parts and service can be found almost anywhere.

You make a valid point regarding parts availability in remote areas and this should be considered when making decisions about boats, engines and destinations.
.
.
.
.
.

Maybe I should dial back a notch on my unfulfilled love affair with a 6LW (or get two - one for spares) . The 855 just doesn't do it for me but hey we are all different and maybe if I lived with a 855 for awhile, I'd grow to love like it.

[mvweebles]

[QUOTE=GoneDiving;3074337]

Originally Posted by mvweebles

Thanks for that. Very informative.

So what's the down side to having a low powered cruiser (say <100hp in a 25t 50 footer) in which the captain has no intention of exceeding say 7 knots:

Not maintaining forward passage in strong currents (wait it out)?
Insufficient power in rough seas?

What have I missed?

A Willard is a full displacement, heavily ballasted, full keel hull. Her only flat sections are the bottom of her keel - she wouldn't do 9-kts with a pair of Pratt & Whitney's bolted to her deck. The 36 footer was designed at 24,000 lbs of which 6000 lbs is ballast, an extremely high percentage even for a sailboat.

The Perkins 4.236 is rated at 80 hp peak.The only time I could imagine needing more power is trying to climb a 20+ foot wave. Many W36s were delivered with an optional Perkins 6.354 rated at around 135 hp. Might get an extra half knot out of her top end with a meaningful cost in fuel burn. But at 7-kts, both engines would be close. Had the Hawaii trip been done with a 6.354, might have needed an extra 30-50-gallons or so, but that's just a guess. Given that W36 only carries 300 gallons, it's not a trivial difference but not zero either.

Bottom line is for true displacement hulls, there is no benefit to over-powering. In fact, there are disadvantages.