Cruising RPM, Hrs, GPH, and longevity Tug and Cut diesels

[rpmerrill]

Brian, Thanks, Good topic for study during the quarantine.

My Info:
2012, R-27, Yanmar 4BY2, The famous BAY RANGER. (https://www.youtube.com/watch?v=gH-E3tTQhZo)
Purchased from Ed and Elaine in 2016.
When I got it, it had about 900 hours on it, and about 7,500 miles on the odometer.
Since than I have only put a couple hundred plus hours on it. I had bigger plans for last year but a couple medical problems slowed me down. Maybe this year.

My log book has more data but it is at the boat right now. I do have a spreadsheet that I compare performance to regularly during the season. Here's part of the data.

Spring 2018 data, all new bottom paint, 50 gallons water and 80 gallons fuel and me. (statute miles)
1000 rpm 5.0 mph 10.1 mpg. 50 psi oil 0 psi turbo 0% load
1500 rpm 6.7 mph 7.1 mpg 61 psi 1 psi 54%
2000 rpm 8.2 mph 4.8 mpg 54 psi 3 psi 55%
2500 rpm 9.6 mph 3.2 mpg 59 psi 8 psi 67%
3000 rpm 11.5 mph 2.4 mpg 62 psi 15 psi 71%
trimmed 12.1 mph 2.6 mpg
3250 rpm 13.5 mph 2.3 mpg 64 psi 20 psi 76%
trimmed 14.3 mph 2.5mpg
3500 rpm 16.2 mph 2.3 mpg 65 psi 22 psi 83%
trimmed 17.3 mph 2.5 mpg
3750 rpm 17.1 mph 2.4 mpg 65 psi 23 psi 90%
trimmed 19.0 mph 2.4 mpg
4000 rpm ? ? 66 psi 23 psi 100%
trimmed 21.5 mph 2.3 mpg

You can see how much difference the trim tabs make. Only above 2500
As I recall on my occasional re-tests, 4000 plus or minus about 50 rpm was the limit.
Also at 4000 rpm the temperature starts climbing. I usually run at about 200 degrees in our fairly warm Chesapeake, but at 4000 rpm it quickly climbs to 205 and I start to chicken out. I've never had a temperature alarm. I think I've read that it trips at 208 or 210 degrees.
My in-a-hurry-fast-cruise-home-before-dark mode is usually 3200 rpm. (The admiral doesn't like running in the dark.)
I only occasionally run above that.
My standard cruise is between 2000 and 3000 rpm, depending upon our schedule.

Only major engine failure is the fuel lift pump. A five hour tow in the moonlight all the way back home, Thanks Boat US. Even being towed, the Admiral was NOT happy.
I had the exhaust hose replaced in 2017. I know it is heavy hose and multi-layered and wrapped but it had a bunch of cracks all over. It got hauled away in the trash before I could do an autopsy but I think the cracking was just superficial, but I chickened out.
I do all my own oil and filter changes. Last year I replaced the water pump impeller, working blind while my friend directed me ..."left, no right, up a little, now move aft, oops you dropped it...." Not sure I'll do that job again.
Not engine related: Replaced both thruster shear pins. Got it down to a system.

Sorry for the bunched up data formatting. I had it all spaced out nicely.
Let me know if I missed anything.
Thanks Brian,
Rich

 

[Salty7]

Brian, your friend with the QSB engines needs to check his EGT, max rpm and oil temps. I have found those engines run oil temps of 250F and that means they should really have synthetic oil in the crankcase because dino oil cokes at those temps. The EGT should be 850F at cruise, no more, if the boat is over-propped they will run EGT of 1150F or higher and that may be why he only got 650 hrs out of his engine. The boat needs synthetic oil, props done right and he needs to make sure he is operating them at their maximum continuous rated rpm or less (usually 90% if I remember but his manual tells him). As my good friend always says "nothing wears out from running too slow or too cool." If those engines are set up properly they easily go 10,000 hrs.

 

[BB marine]

Brian, your friend with the QSB engines needs to check his EGT, max rpm and oil temps. I have found those engines run oil temps of 250F and that means they should really have synthetic oil in the crankcase because dino oil cokes at those temps. The EGT should be 850F at cruise, no more, if the boat is over-propped they will run EGT of 1150F or higher and that may be why he only got 650 hrs out of his engine. The boat needs synthetic oil, props done right and he needs to make sure he is operating them at their maximum continuous rated rpm or less (usually 90% if I remember but his manual tells him). As my good friend always says "nothing wears out from running too slow or too cool." If those engines are set up properly they easily go 10,000 hrs.

Keeping a watch on EGT on small diesels is important too. Especially engines with aluminum blocks and cast in liners or engines with aluminum heads and cast iron blocks. Two metals with different expansion rates. The best way to keep these temperatures down is do not over prop do not over load the engine.

I'm sure all your information is correct. He never had the engine torn down to troubleshoot the failure mostly because he knew he ran the engine hard and he has deep pockets. He has participated in formula 1 racing for 50 years so he is not shy with the (petal to the metal). He was coming across Lake Michigan when the engine started knocking. He ran the engine at 80% load all the time 90% WOT. By the time he arrived in Chicago (one engine) He had already called the marina and had a new QSB on order. After installing a new engine in the boat he traded the Searay in and just took delivery of a 2020 Fairlane Targa 48 with twin Volvo D6 440hp IPS.


If those engines are set up properly they easily go 10,000 hrs.[/quote]

The engines need be set up properly meaning capable of turning max manufactured rpm for rated HP plus operated at or near 50% of maximum load to achieve maximum longevity. The Cummins factory Rep that witnessed the new engine install told my friend that run the high output QSB hard expect 1500 to 2000 hrs. Run them easy expect up to 10,000 hrs. He could easily do that in the 47 Searay. The boat cruised at 32Kts at 2700rpm and at 2200 rpm he could still maintain a plane at 21kts. (max RPM 3000)

My point of this thread is to see where we all run our Tugs and Cuts what kind of performance are we experiencing, what issues are we seeing, How many hours of run time is experienced ?

I see a lot of discussion and speculation about this topic but has anyone had a block or engine failure that would have been caused just by use? I figure at average 30 mph a car engine runs 6000 hours easy granted at lower load.

This is a good question when it comes to the small displacement diesels, actually a question I'm asking too. I have seen plenty of car and boat gas engines with high wear and in need of freshening up or rebuilt.(1000 to 1500 hrs on boats) (I have no idea Hrs in cars) I have rebuilt several outboards and inboard gas engine because of wear in past years. I have removed several diesels from boats that needed freshening up. Most were sent to Patten caterpillar or Cummins for rebuild so I can't speak about the condition other than they needed to be rebuilt.

My Info:
2012, R-27, Yanmar 4BY2, The famous BAY RANGER. (https://www.youtube.com/watch?v=gH-E3tTQhZo)
Purchased from Ed and Elaine in 2016.
When I got it, it had about 900 hours on it, and about 7,500 miles on the odometer.
Since than I have only put a couple hundred plus hours on it. I had bigger plans for last year but a couple medical problems slowed me down. Maybe this year.

Thanks Rich for your Data, It looks like your Yanmar performance numbers are compared to as new with 900 hrs. It would be interesting to have average engine operation from past owners. I going to say the boats average cruise was in the 50% to 60% range.

 

[tlkenyon]

So, the my D3-150 redlines at 3,000 and the D3-220 redlines at 4,000. Since they have the same internal components except maybe a turbo, and the difference is in the software, is it reasonable to expect that the D3-150 will last longer because it cannot go above 3,000? For instance, if I run my D3-150 at 2,900, that is only 72.5% of the component-capable D3-220 redline. I may not have expressed this very well, but do you see what I am getting at? Will de-rating the D3-150 have the effect of more longevity?

 

[BB marine]

So, the my D3-150 redlines at 3,000 and the D3-220 redlines at 4,000. Since they have the same internal components except maybe a turbo, and the difference is in the software, is it reasonable to expect that the D3-150 will last longer because it cannot go above 3,000? For instance, if I run my D3-150 at 2,900, that is only 72.5% of the component-capable D3-220 redline. I may not have expressed this very well, but do you see what I am getting at? Will de-rating the D3-150 have the effect of more longevity?

I see what you are getting at. From the many articles I have read plus adding practical experiences of engine rebuilding and refinery machinery rebuilding I have found when a engine /machinery is operated at above 50% of its design the longevity decreases. When machinery is operated at 80% or above of its design the longevity is significantly decreased and the percentage of a major failure is greater due to the additional wear and stress on the machinery. Normally when a manufacture designs an engine or Machinery there is a "service Factor" built in the design. Meaning if the machinery load requirement is greater than its designed capacity it will still operate for short periods of time without failure.

The D3, Base engine 110 Hp, Block, head, crankshaft, camshafts, bearings, after cooler, exchanger, turbo charger are all the same. All internal components in a 110hp are the same as the 220hp.Engine mapping and rpm are the variables. Meaning Volvo has designed the D3 2.4L diesel to be capable of producing 220 hp reliably for (example 3000hrs) based on an average life time load at 40%. I calculate load based on fuel consumption. 100% load equals 12 gph =220 hp. Using this formula 4.8 gph = 40% load 88 hp, 6 gph = 50% load 110 hp, 7.2 gph= 60% load 135 hp, 8.4 gph =70% load = 155 hp, 9.6 gph= 80% load = 176 hp , 10.8 gph= 90% load =199 hp. The magic number (my opinion) for designed longevity of the D3 2.4L engine using 3000 hrs as a base line is average fuel consumption 4.8 gph during the 3000 hours of operation. Regardless of the HP rating. Example: if you put 300 hrs on your engine in a season and burned 1440 gallons of fuel your average fuel burn would be 4.8gph. If you are under that the Boat and engine manufacturer did a good job designing the package. The mechanical stresses on the D3 using 6 gph are the same with a 110hp or a 220hp. The 110 is at 100% load of rated hp the 220hp is at 50% of rated hp but equal stresses and wear on both engines.

Assuming the fuel burn of a 150Hp D3 Based on Chimo's numbers 7.5 gph WOT =140hp which is 100% load based on 150 hp rating but the same stresses and wear that a 220 would have at just over 60 % load.

The same theory can be used with Yanmar, Same Block same internal components same displacement, 110hp 150 hp and 180 hp.

The same theory Mercruiser 2.0L 115 hp to 175hp.
The same theory can be used with the D4 175Hp base engine highest output 320hp, D6 300hp to 480 hp.

By far the most important component is confirming The engine will rev to its maximum recommended rpm regardless of how you operate the engine. Tuning a prop to maintain maximum rated RPM is cheap maintenance. Over propping changes design perimeters even a 2000rpm.

 

[NorthernFocus]

...From the many articles I have read plus adding practical experiences of engine rebuilding and refinery machinery rebuilding I have found when a engine /machinery is operated at above 50% of its design the longevity decreases. When machinery is operated at 80% or above of its design the longevity is significantly decreased and the percentage of a major failure is greater due to the additional wear and stress on the machinery...

If this statement is regarding combustion engines it is more or less accurate. If "machinery" is meant to include the broader spectrum of machinery of all types this is not true. Centrifugal machinery in particular operates best at/near its design capacity(i.e.full load). If fitted with with oil film bearings(aka sleeve bearings) many machines can operate at full design capacity indefinitely without any maintenance at all on the core machine.

... Normally when a manufacture designs an engine or Machinery there is a "service Factor" built in the design. Meaning if the machinery load requirement is greater than its designed capacity it will still operate for short periods of time without failure...

It would be nice if boat/engine manufacturers pointed this out more clearly in their stated HP ratings. Unfortunately advertised rated HP on engines tends to be inclusive of the service factor.

Generally speaking heat is the enemy of machinery and particularly of combustion engines. For that reason the discussion of fuel consumption and wear for a given core engine is basically sound. That's also the reason that purely looking at total engine hours as an indication of engine life is given way too much emphasis.

 

[BB marine]

If "machinery" is meant to include the broader spectrum of machinery of all types this is not true. Centrifugal machinery in particular operates best at/near its design capacity(i.e.full load). If fitted with with oil film bearings(aka sleeve bearings) many machines can operate at full design capacity indefinitely without any maintenance at all on the core machine.

You are for the most part correct in this statement. Centrifugal equipment may not apply. Turbines run 24/7 between 5 to 10 years at designed output and rates. I'm not sure that equates to 100% of the capacity. I have made repairs to turbines because production demands required rates increased to above design. During this time the "pad bearings" temperatures are monitored ( active thrust bearing ) to prevent failure. In a few cases the increased temperatures because of reduced lubrication from the added pressure on the bearing reduced the longevity of the machine and required a shut down.When this happened to a few of the machines I worked on, engineering made design changes so higher rates were achievable without damaging the bearings. Hence I'm not sure all of these centrical machines run at 100% of the capacity. When I made the statement (machinery ) I was referring to reciprocating machinery and gear box's. Torque loads operated at higher designed load limits, longevity was at a noticeable decrease as I believe the smaller displacement Diesel engines operated at the higher designed load limits will see a noticeable decrease in longevity.

That's also the reason that purely looking at total engine hours as an indication of engine life is given way too much emphasis.

I agree hours should only be used as a baseline for design. 1000 hrs of use means nothing really. 1000 gallons of fuel used is how much energy the machine has produced.Energy produces heat and heat in my thinking means wear. I was talking to a boater at a local anchorage ( actually it was an area for beaching) The boat owner was always there. I asked him how many hours a season he puts on his engines. He said " not many I leave the marina and run WOT to get here every weekend so I don't put many hours on the engines. Most of these guys put twice the hours as I do in a season. My engines will last twice as long" I had no comment just took another sip of my beer. Really! :shock:

Good comments Dan. Based on your work experience you have more knowledge in this area than I do.

 

[Red Raven]

Here’s my data. I’m interested to see if any others have seen a reduction in performance like ours.

2014 R27 (purchased used with 30 engine hours in 2015)
Volvo D3-200
All numbers fully loaded

100 Engine hours (2015)
Slow cruise: 2250rpm 7.3kts 2.8gph temp 178F
Fast cruise: 3400rpm 14kts 8gph temp 183F
WOT 2015 4000rpm 19kts 10gph temp 189F

1180 Engine hours (2019)
Slow cruise: 2250rpm 7.3kts 2.8gph temp 178F
Fast cruise: 3400rpm 13kts 8gph temp 189F
WOT 2019 3850rpm 16.5kts 10gph temp 196F

As you can imagine I am pretty concerned about these numbers. The reduction in WOT has been consistent at about -50 rpm per year. I have removed nearly everything from the boat (over 1000lbs including the dinghy and spare anchor and chain etc.) as a test and only achieved a 50 rpm improvement. Changed the impeller, back flushed the heat exchangers and cleaned the running gear (it was not bad). No improvement. The boat lives inside on the trailer over each winter and thus the bottom is pristine at launch each season but the drop in WOT rpms continues.

The first 4 years we ran her pretty hard, fast cruise 80% of the time. Last year was the opposite with the trip up the inside passage. 90% slow cruise, 10 fast cruise. The years at fast cruise show iron count at the high end (at 200 hours). Last year with slower cruise average iron count was down to mid normal range (again at 200 hours). I fully service the boat myself per the Volvo schedule (at less than 200 hours). Never seen more than a small crack in the impeller at changeout.

A certified Volvo tech went out with me at the 2019 Rendevous and put his computer on it. He could find nothing wrong and said it must be bottom condition and/or load. I had already removed a lot of weight and the bottom had 6 months on it since cleaning but the performance had been the same all year.

This off season, to get the WOT rpms up, I have removed the cup from the 17x17 prop. I also ran barnacle buster through the raw water system and cleaned the turbo with one of those turbo spray cleaning products. I haven’t launched the boat this season to test these changes yet. If no improvement I plan to take it to a shop to have the injectors cleaned or replaced. Can’t think of what else to do.

Other than the WOT reduction issue the boat has been completely trouble free. Love the boat.

Curt

OK, the results are in and somewhat surprising. I launched the boat for the season this past week. Per the above I was really interested in what effect removing the cup from the prop would have. The prop shop predicted around A 100 rpm increase at WOT. Well...I got a 310rpm increase! Here is the new data.

Spring 2020 propeller cup removed (conditions: 3/4 fuel, full water, dinghy and dinghy motor on swim step, 1 person, 3/4 gear, no food or drinks).
Slow cruise: 2250rpm 7.0kts 2.5gph 174F 2.6TBpsi
Fast cruise: 3400rpm 11.8kts 6.6gph 183F 17TBpsi
WOT: 4160rpm 17.8kts 9.4gph 192F 22TBpsi

Note that in addition to increased WOT rpm, there was a corresponding decrease in fuel burn, speed, and temperature for a given rpm. While I was thrilled to see the reduced temperature and reduced fuel burn, of course there was the expected loss in speed as well which didn’t make me quite so happy. 🙁 I expected to have around a 5% loss in speed. I did not expect a 10 to 15% reduction. Of course this is consistent, however, with the much greater increase in rpms than planned. Also the speed difference can be recovered by now running at higher rpms if desired. In fact, WOT speed is now higher than it was last fall because of the much higher rpms, (but not where it was when new).

At this point, I think I am a bit under propped which is probably not a bad thing because I had only one person in the boat and 3/4 gear, and no food or drink.

Caveats: As noted previously, there were other variables that changed from last fall including; fully cleaned bottom, barnacle buster flush of the raw water system, and turbo cleaning with a direct spray injection cleaning product. It is possible some of the changes were due to one or more of these items. The temperature reduction certainly may be partially from the raw water system cleaning. The turbo cleaning effect is an unknown as I do not have good turbo pressure numbers from prior except at WOT. At WOT the turbo pressure has actually dropped a bit but perhaps that is just due to the reduced load from prop change. The changes in speed, fuel burn, and WOT rpm are consistent with a reduced load (propeller change).

One last unknown is that the prop shop did note that one blade was slightly out of spec (slightly bent?) when it was initially inspected. This was repaired when the cup was removed. I am curious enough about this that I am tempted to pull the boat and install my unmodified spare prop to remove the other variables. I just may do that if more boating options don’t open up around here soon. Otherwise I just want to get out there boating!

 

[BB marine]

Wow that is a big increase in RPM and good data to compare. The bottom being clean could have helped slightly. The bent prop although not much could have a noticeable effect depending on where on the blade and how much of a bend. An additional passengers and supplies will make a difference but you have room to move with your rpm being 4160 rpm. I personally would rather have it a bit higher than below Max rating of 4000 rpm.

What prop are you running? How much cup did they remove?

I have a 17 X17 1 1/4 with a .105 cup.
I called Acme last week and spoke with Todd about a slight decrease of cup to give me an additional 100 rpm when I'm loaded heavy while doing extended cruising. He ran calculations based on the 2.03 reverse gear ratio 4000 rpm rated engine. He told me to go to a Acme dealer in Chicago, Air Marine and have them confirm the exact measurement of the prop. If it is in factory specs then .075 cup needs to be removed from the .105 He said removing any more it would reduce the efficiency of the prop to much. It would be better to drop to a 17 x 16 x .105 cup prop. Removing the .075 would increase rpm by 100 to 110 rpm and reduce speed by 5%. I hope I see the same results has you. Your first test run your engine at WOT is running just under 90% based on your fuel consumption. Based on those numbers running loaded you should still be able to run at 3400 rpm at just over 60% load based on fuel consumption. I'll sacrifice a knott for a little less load on the engine. Remember the reduction in load is not just at WOT it is through the full rpm range of the engine. The reduction in fuel consumption correlates to the reduction in load. You may be running slightly under propped but I would wait to see how it is when fully loaded.

 

[Red Raven]

Hi Brian,

My prop is a 17x17 and “was” a .105 cup. I don’t know how much cup they removed but I can find out. I have the measurement sheet on the boat but not with me at the moment. I’ll also give them a call.

Curt

 

[tlkenyon]

I talked to my Volvo mechanic about engine longevity. I have an R25sc with D3-150. He is a construction equipment mechanic, as we have no boat diesel mechanics here in South Dakota. He indicated that the D3 in its various flavors is used extensively as a gen-set engine in the construction industry, and that is why he feels he can responsibly service my engine. He confirmed that the engine in my boat (has had serviced it so he knows it) and the gen-set engines are the same except for the cooling and wet exhaust marinized systems. The gen-set engines run at a constant RPM throughout their lifetime, which he says is upward to 10,000 hours before rebuild. The rpm is typically 3,600 to produce 60hz power. Their are some that run at different RPMs, those that are coupled to SCR-electric systems (whatever that is) that are less dependent on engine RPMs. Don't want to upset the apple cart, but kinda interesting information....

TK

 

[ALICE J]

Hi Brian and others, a lot of what has been discussed is way over my head. I find this an interesting thread and I would like to add to the discussion with some caveats. I am A cruiser and gunkholer my eyes are not on the gauges but on the lurking rocks beneath the water and the soaring Eagles in the sky above. A few of the things that are talked about on this thread are very intimidating to myself who is not a numbers person.

I have a Ranger 27 2011 with a Yanmar BY4180, presently with 22OO. The only issue I’ve had with this engine was a burned-out relay that controlled the fuel pump. It took Mastery Marine about a week to figure out what the issue was but we did get it fixed from Napa. That occurred at about 1330 hours. At about 1500 hours I replaced all the engine hoses and engine mounting blocks just as a precaution as the boat was about six years old. I travel between 5 to 6 1/2 kn burning 1 to 2 gallons per hour. RPM between 1750 and 2250. I have the standard ranger prop occasionally will go wide open and achieve about 13 knots, I do have fins on the trim tabs, but in defense of the 9 gallons per hour my vessel is very heavily laden about 11,000 pounds with all my “necessary” stuff . I also tow my RIB in Avon rover and when I go above eight knots the RIB gets very squirrelly. My cruise temperature is about 196-8 degrees . At WOT my temps rise to 208 and I back off the throttle in about 5-10 minutes . I used to change the oil every hundred hours last year we reread the manual and change every 250 hours with new filters. I have not had an oil analysis. I plan to have the injectors reset this summer. I have had to rebuild both bow thruster and stern thruster with new enclosed bearings and brushes. Apparently condensation rusted the bearings and froze the brushes. The stern thruster needed a new gear leg as water had gotten to the gear case. Was losing antifreeze and found the culprit to be chafed hose for the heater hose as it rested upon the dipstick support.

When may I expect to have alternator or starter issues. Doing the Canadian canals the starter got a terrific work out now in the Bahamas with the refrigerator and freezer operating the alternator it’s certainly getting a lot of juice. Would a rebuild or new be in the near future. I replaced the packing in the stuffing land at about 2100 hours, but the bilge was really clean :roll:

 

[Newf]

I liked your post Alice J so I will follow your lead and add some info, but for those who own the baby of the fleet. I tried to post this before but for some reason it didn't post.

I have a 2014 21-EC with the Volvo Penta D1-30. Currently has 2160hrs. Used 90% of time for fishing so mostly trolling hours on the engine.
Fuel burn is irrelevant to me since it burns so little and WOT it will still do 9.5 knots so no apparent loss of speed or power at this point.

Oil and Fuel filters are replaced as per the Maintenance schedule.
Impellers have been replaced at up to 500hrs for the first one and as low as 108 hours on another occasion but usually 250-300 hours in the norm. On every changeout there have been cracked vanes of varying degrees but no complete vane failure at this point.

I trailer the boat so I'm only on my second set of Zincs except for the thruster which is on the 4th one.

I had a corrosion issue on the discharge side of heat exchanger that I was fortunate enough to be able to repair with Marine Tek. Salt water had seeped between the two o-rings and corroded the casting. This occurred around the 1300-1400hr mark. Cleaned up the exchanger core with an acid bath during this repair. After this issue I started to flush the raw water system after every launch and drain the exhaust elbow.

I had to replace the engine mounts and did this around the 1800 hr mark although signs of minor cracking and rubber fatigue was noticeable much earlier than that. With only about 400hr since the changeout I'm starting to notice minor cracking starting to appear in the rubber again. I'm sure the low idle and higher engine vibration at trolling speed is the main issue here. Stuffing box has only been adjusted twice.

I'm on my 3rd bilge pump. The first one was replaced under warranty. The second one failed after 1400hrs. It apparently came on, stayed on and melted parts of the pump and sensor. I've since installed an indicator light so I can see when the pump kicks in. If it's on for more than a 10-15 seconds I know that it's probably means that the sensor needs a good cleaning.

I've adjusted the valves twice but will do so every 500hrs going forward.

I'm considering the addition of oil pressure and temperature gauges to allow for better monitoring of engine condition going forward.

Would be interested in issues, if any, that other D1-30 owners have had. Would also be interested in suggestions on other things that I should be doing.

 

[Red Raven]

Hi Brian,

My prop is a 17x17 and “was” a .105 cup. I don’t know how much cup they removed but I can find out. I have the measurement sheet on the boat but not with me at the moment. I’ll also give them a call.

Curt

I found the sales receipt. Says “Remove Cup”. I called the prop shop. They said that means they removed it all. Based on my performance and their SW program they said that is what was required. They seemed a bit surprised with an increase of over 300rpm but not really that surprised. I think it is a bit of a shotgun process. The measurement sheet from them is all about measuring pitch and nothing about cup. Based on my research there is not even agreement on a standard measurement for cup and no way to really know the full effect without a bit of trial and error. The shop said removing the cup “can” be equivalent to reducing anywhere from 1 to 2 inches of pitch. The shops recommendation was to either leave as is and load the boat up, add back 1/2 cup (.05) to the modified prop, or remove 1/2 cup from my spare (easier and cheaper to do) and install that one. In any case I will put my spare factory spec prop back on the boat and test that to eliminate other variables before making any more mods.

Curt

 

[BB marine]

Based on my research there is not even agreement on a standard measurement for cup and no way to really know the full effect without a bit of trial and error.

Air Marine propeller shop in Chicago uses computerized coordinate measuring system called Prop Scan. This is used for the inboard propellers. According to Acme propeller there is a formula to figure out how much cup can be removed. Todd from Acme said do not remove all the cup be cause the prop will loose to much efficiency. When I dropped off the prop and told them what I wanted done .075 removed he thought that may be too much. He needed to scan the prop first to see exactly what the numbers were before removing that much cup. Todd was very confident that .075 would increase 100 to 110 rpm. I hope he is right I don't need 300 rpm increase. I haven't heard back from them. Chicago area is still in a strict Covid 19 protocol.

I think your plan is good you can compare apples to apples now. Compare the original prop to the adjusted prop. this will give you a better idea of how much cup to add back if needed. It will also show you gains from work done over the winter.

 

[Red Raven]

Hi Brian,

Based on my experience you may want to consider removing less than .075 to get 110rpm considering I got 310 rpm by removing .105. The other work done on my boat could be at play though and the cup vs. rpm may not be linear.

Thanks for your feedback and good luck!

Curt

 

[BB marine]

I talked to my Volvo mechanic about engine longevity. I have an R25sc with D3-150. He is a construction equipment mechanic, as we have no boat diesel mechanics here in South Dakota. He indicated that the D3 in its various flavors is used extensively as a gen-set engine in the construction industry,

I would be interested in the model generators that use the D3 ( Volvo built the engine exclusively for automobiles) I have searched many times for other applications the 5 cylinder 2.4L diesel is used in. Most Volvo diesel electric plants use a 4 cylinder commercial designed engine. Most portable diesel generators used at construction sites are heavy duty 1800 rpm 4 pole,60HZ light plants. And last thousands of hours. Most light duty 3600 rpm generators 2 pole (half the windings as a 4 pole) use gas engines or small light duty diesel engines and have less longevity. Rated at 1500 hrs to 2500 hrs based on the engine design. Many are (throw aways) some are rebuildable.

The information that your mechanic provided says that the D3 used in the generators he services have much higher service longevity than most light duty generators. Knowing the power plants theses are used in and the Hp requirements (loads) to operate the generator would indicate acceptable loads to extend longevity of the D3. During big jobs at the refinery we had several 30KW diesel generators with 2.0L Diesels that burn 2GPH average and rated at 36HP @ 1800rpm. All the generators we used were 4 pole 1800 rpm.

Thank you for your post good information.

 

[tlkenyon]

Brian,

My information was most certainly anecdotal. I will check with the mechanic next time I see him. Thank you for your very consistent expertise and posting. I hope everyone out there appreciates your efforts as much as I do.

I have just over 1,000 hrs on my 2015 D3-150 and hope to get a lot more. Out Loop adventure really stacked up the hours.

CHEERS

TK

 

[BB marine]

Brian,

My information was most certainly anecdotal. I will check with the mechanic next time I see him. Thank you for your very consistent expertise and posting. I hope everyone out there appreciates your efforts as much as I do.

I have just over 1,000 hrs on my 2015 D3-150 and hope to get a lot more. Out Loop adventure really stacked up the hours.

CHEERS

TK

We are planning on full time Looping starting this fall. One of my reasons for researching longevity. I want to run the engine in the upper rpm range at least 50% of the time. I also want to maintain longevity the best I can. Keeping the engine loaded properly I think is an important component. The purpose of this thread is to get opinions and results others have experienced .




Alice J had good information. The engine hours of trouble free operation is possible with these small displacement engines. The information I took from his post is he is loaded heavy but also runs in the lower rpm range and burning average 2 gph which is operating at average 30% load. While not running at high rpm often I think there is still a benefit to prop adjustment. It sounds that he may be over propped based on the data that Rich posted on this thread. Rich's numbers are much higher at WOT. Remember the WOT rpm determines" how steep the hill is that the engine is climbing" no matter what rpm the engine is running it is still climbing the hill". Alice J's reliability is very promising based on his experience.

D1 information. I will say out of all the engines used in the Fluid Motion fleet I would expect the longest longevity from the D1. The D1 67 cubic inch displacement and 30 hp over 2 to 1 ratio . The D3 2.4 cubic in 146 cubic in 220 hp ratio is .66 to 1 (cubic in to HP) The 150hp D3 ratio is better 1.02 to 1, The 200 hp is .73 to1, D4 300hp is .75 to 1, D4 260 is .86 to 1. The rule of thumb is a 2 to 1 ratio = longevity. A D3 rated at 70 hp would have a 2 to 1 ratio similar to the D1. So in theory rate your D3 at 70 hp approximately 4 gph. or D4 at 110hp 6gph and you may see the hours of longevity 3000+.

This is the chart for engine rating. All Volvo's, Yanmars, and Mercruisers used in Rangers and Cutwaters are M5 rating.

M5 Rating

Typical Load Factor≤ 35%

Typical Annual Use ≤ 300 hrs

Typical Full Power Operation. 0.5 of each 8 hr

M5 points to engines for recreational cruising boats. The manufacturer is telling us that the M5-rated engines will maximize longevity when those three parameters are met.

35% load factor would be average fuel burn rate of 4.2gph . Using a D3 as an example: A boat used 5 seasons with 1500 hrs with 93.75 hrs of WOT and 6300 gallons of fuel burned would be used per design. The D3 is built and designed to operate 3000 hrs when operated within the above parameters. Theoretically if a engine is run at the maximum parameters of the M5 rating 3000 hrs would be expected "end of Life" If parameters are higher operation hrs are less if parameters are lower operation hrs are higher. In my statement made in an earlier post I said I expect my engine longevity to be 1500hr to 2000hrs. If I operate at a load factor of 75% which would be cruising at 9gph 3500rpm and have an 6 gph average fuel burn at 1500 hrs I would have burned 9000 gallons of fuel and at 2000 hrs 12000 gallons of fuel. The engine that was run at the maximum limits of the M5 rating would have burned 12600 gallons of fuel at 3000 hrs.I realize these are crazy numbers. There is a real easy way to see where your parameters are. The Volvo EVC display shows average GPH. When you take a trip at the end of the day log the information displayed. If the GPH is higher than 4.2 gph for the day you are running above 35% load for that day. Many days it may be lower, keep a good log to average it. You can also use it for your maintenance schedule. Every 100 hr oil change may be to soon if you burned 300 gallons of fuel in the 100 hrs but if you burned 450 gallons of fuel it may be time.

 

[ALICE J]

Bored with a tropical depression just north of my location with winds steady 20 mph gusting to 25, by Friday expected to gusty into low 30. My location is N27.5.2256. W78.1.1643. Very protected!

So to break the malaise, I looked back through my log and retrieved these numbers: engine hours 271, miles run 960, gallons of diesel 347. 100 hours on Mase 2.7 generator. This was just for the Bahamas trip, left Nov 7 2019, through Abacos, to George Town, Exuma, am now heading for Florida via the Abacos.

Would the number crunchers tell me if I’m doing okay? Or should I be more aware of additional numbers. :shock: