3208T on 44 ft Gulfstar

Trawler Dreamers · Jun 11, 2011

Does anyone have experience with the 3208T Cat in a 44 ft Gulfstar or comprable boat?

Would this power and boat combo be happy drifting along at 1100 to 1300 RPM? I understant I should run higher RPM some of the time but would a study diet of very slow speed cause any problems and what would be a realistic fuel burn rate at the slower speeds?

We are pretty determined to do the slow crawl thing. Sounds like the life we want to live. We have also become interested in the Gulfstar because of some of its features such as large gallley and easy engine room access.

Thanks for the help.

Dreamers

FF · Jun 12, 2011

While it will slowly be killing the engine , and not at all fuel efficient , most folks dont care.

The 3208T will frequently run 5000+ hours of normal (half throttle) use.

The usual minor hours of a trawler 300? a year will take a decade to get to 3000hours .

A 20 min shot of heavy throttle every 10 hours will help.AS operating at at least 1 lb boost would also help.

Many old engines simply had the turbo added , not a special turbo build with lower compression ratio pistons etc.

Perhaps a conversion to an NA is possible with simply tossing the turbo?

"would be a realistic fuel burn rate at the slower speeds?"

This will be up to you to figure , and will be interesting as a higher speed 7K or 8K might not cost any more than 5K due to engine efficiency.

A Flow Scan will answer the question easily, for a price.

Trawler Dreamers · Jun 14, 2011

Thanks for the input.
At this point, the gross tonnage of what I do not know is pretty astounding. However, I did realize low RPM might cause problems. Just did not know the nature of the problems.
Dreamer

FF · Jun 15, 2011

Just did not know the nature of the problems.

The problem is called underloding.

The combustion pressure must be high enough to get behind the rings and push them hard against the cylinder wall.

When this does not happen the rings do not seal and the cylinder is burnished , which removes the hone marks that hold oil on the cylinder walls.

So oil consumption goes up ,compression goes down , fuel consumption to create the came power goes up.

In addition the poor sealing rings will allow more blow by into the crank case , contaminating the oil quicker.

This is a slow procedure and effects mostly engines that are larger and heavier duty than a 3208.

Weather it will occur in the limited use a yacht gets is uncertain.

Commercials will frequently have 2 gen sets , day heavy load, nite about 1/3 the size , so the diesels are properly loaded.

Mostly on a yacht you are stuck with what the advertising guys wanted when the boat was assembled.

Avista · Jun 15, 2011

I run my 3208TA engines typically between 1100 and 1250 rpm. They run at normal temperature at these rpm's with no issues They don't smoke or load up and seem quite happy. Regular oil samples actually show excellent (little) wear and Blackstone Lab reports usually show better results than than the "normal" baseline they use. I spent quite a bit of time researching slow speed operations on these motors including spending over an hour on the phone with Caterpillar marine applications. Cat does recommend operating the engine at normal cruise setting of 80% power for short periods when used this way. I am not at the boat where I have the information, but if memory serves it seems like 10 minutes for every four hours. Feel free to PM me if you want me to check when we go over to the boat on the weekend. I also have power setting, speed and fuel charts from test runs over measured distances which I am happy to share, but they are specific to my boat of course.
With regards to FF's comments, he may be correct, I can only tell you what my personal experience is with these motors. I have 1700 hours on mine and they use less oil than the book calls normal whe run at the low rpm (about one quart in 20 hours) vs the normal 1 quart in 8 hous at 2100 rpm. Maintenance has been minimal with hundred hour oil changes ( mine hold 16 quarts each) and zincs about every 8 months. You do also need to change the coolant in these at regular intervals as well, and you can get all the info you need from the Cat marine website regarding the maintenance schedules.

BelfastCruiser · Jun 21, 2011

My single 3208 natural has a sweet spot @ 1750 rpms which pushes my 42' trawler along @ just over 8 knots. I can't tell from your post whether the Gulfstar has a single or twins. Enjoy your boat search!

jcwyatt · Jun 21, 2011

I have twin 3208T 250hp cats with 1100 hours. I run between 1800 and 2000 rpm, 8 - 10 knots.

Its a 54' trawler with a 17' 6" beam.* I have only had the boat a year but so far they have started and run great. I have had to rebuild the raw water Jabsco pumps and change filters, oil, zincs, basic maintenance stuff. I have heard I should get 8000 - 12000 hours from the lower horse power cats.

Alemao · Jul 23, 2011

I'm buying a boat that has 2 cat 3802, 375hp, 2,000hr and I intend to come (I'm writing from Brazil) back to Brazil. I think that we'll spend about 650hr.
I need to know what I have to buy and store to has a healthy engines, like spare parts, oil, filters,...
Somebody can help?

-- Edited by Alemao on Saturday 23rd of July 2011 09:24:49 AM

Delfin · Jul 23, 2011

Avista wrote:
I run my 3208TA engines typically between 1100 and 1250 rpm. They run at normal temperature at these rpm's with no issues They don't smoke or load up and seem quite happy. Regular oil samples actually show excellent (little) wear and Blackstone Lab reports usually show better results than than the "normal" baseline they use. I spent quite a bit of time researching slow speed operations on these motors including spending over an hour on the phone with Caterpillar marine applications. Cat does recommend operating the engine at normal cruise setting of 80% power for short periods when used this way. I am not at the boat where I have the information, but if memory serves it seems like 10 minutes for every four hours. Feel free to PM me if you want me to check when we go over to the boat on the weekend. I also have power setting, speed and fuel charts from test runs over measured distances which I am happy to share, but they are specific to my boat of course. With regards to FF's comments, he may be correct, I can only tell you what my personal experience is with these motors. I have 1700 hours on mine and they use less oil than the book calls normal whe run at the low rpm (about one quart in 20 hours) vs the normal 1 quart in 8 hous at 2100 rpm. Maintenance has been minimal with hundred hour oil changes ( mine hold 16 quarts each) and zincs about every 8 months. You do also need to change the coolant in these at regular intervals as well, and you can get all the info you need from the Cat marine website regarding the maintenance schedules.

*Cat uses an oil cooler that also functions as an oil heater at low revs because it uses an exchanger with the cooling system.* So you get an oil temperature equal to the thermostat at pretty much any rpm above idle.* The 3208 and 3306 that I am most familiar with will not have problems with low rev operation, and you won't pay a price in loss of fuel efficiency either.* As Cat recommends, just run it up to near max rpm for 30 minutes or so every 8 hours and the engine will last as long as it would if operated at 75% all the time.*

It's been a while since I drove one, but I seem to recall that the 3208's we had in trucks ran about 90% of the time at 1100-1200 rpm.* Our loads were light and lots of highway miles.* We typically got 750,000 miles without touching them and I guess that would translate to 15,000 hours or so.* 3306s routinely go 25,000 hours in applications where they idle a great deal.

FF · Jul 24, 2011

The simplest way to get some loading and not gum up the turbo is to install a turbo pressure gauge and operate ai 1psi as a minimum,

nskarlgreen · Aug 5, 2011

At least three posts point it out but will say that we use these engine in forty foot jet boats for the navy and they are a very robust and reliable engine. As Avista wrote periodic load helps but they do have a cooler as delfin mention that functions as a heater. All good points. For our larger generators on ship because of the low load requirements we run them for about an hour in a 24 hour period at sustained load of 100 percent approx. We have a overload capacity so they can operate at that without tripping. Decoking as we call it can be done at lower loads just extend the period of time. As quoted somewhere else it has to be above eighty percent or higher. We use a minimum of seventy five percent. This comes about with our ships because we have four generators and one is enough for full load most of the time but because we can black out we use two. Another option if your still concerned is we have started using low load injectors for the generator engines annd cat might have some to look into. Of course our requirement is for around the clock operation at sea of at least one generator and one of our engines usuallly a twenty cyl cruise diesel we have. Great advice from avista hope you took him up on the charting it will settle your worries and can anybody drive anything without goosing it occassionally....happy cruising.

martikev · Mar 19, 2021

jcwyatt said:
I have twin 3208T 250hp cats with 1100 hours. I run between 1800 and 2000 rpm, 8 - 10 knots.

Its a 54' trawler with a 17' 6" beam.* I have only had the boat a year but so far they have started and run great. I have had to rebuild the raw water Jabsco pumps and change filters, oil, zincs, basic maintenance stuff. I have heard I should get 8000 - 12000 hours from the lower horse power cats.

What is your fuel burn at 8 knots?

3208T on 44 ft Gulfstar

Trawler Dreamers

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FF

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Trawler Dreamers

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FF

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Avista

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BelfastCruiser

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jcwyatt

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Alemao

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Delfin

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FF

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nskarlgreen

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martikev

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