420/44 DB Owners Club

Islandtime04 said:
I went from a 400 SB with 454's, to a 420 with the 480 CE's and absolutely love, love them. I noticed the biggest performance difference was a following sea condition. Rock solid. Good luck.
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Thank you! This is my first go around with diesels. Going from 8.1 gassers in my 390 MY to 500 QSCs in the 44!
 
Irie308 said:
Congrats! Nothing like the first few runs when going from gas to diesels!
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Looking forward to that first run...will be a long one from the location of the boat to home port, about 300 miles!
 
That's my only wish; better range...It's about 220 miles at cruise speed.(+-10% reserve).
 
Islandtime04 said:
That's my only wish; better range...It's about 220 miles at cruise speed.(+-10% reserve).
Click to expand...
What is "cruise speed" on the Sedan? There is actually a marina with diesel just about half way on my maiden voyage!
Rob
 
I have an older generation of the 8.3 and the 500's are common rail so you'll have better efficiency. (I always laugh when we talk efficiency on boats). Actual speed and consumption varies +/- 1-3knots based on many factors (current, weight, temp, fouling levels, etc.), but generally I cruise between 20-23 knots. 2250rpm seems to be the sweet spot for me. That's about 80% load burning 32-34/gal.hr. Others on this thread with your exact engines may have other thoughts.
Also recommend bookmarking Tony Athen's site.
https://www.sbmar.com/engine-info/cummins-qsc-specifications/
 
Agree with Islandtime. Watch the load on the motors and keep it at or below 80%. Cruise speed on my last boat, which was same year and motors as yours, was about 2300. At this power, depending on weight on board I would cruise at about 23-24 knots and the load was less than 80%. You'll be burning about 34 GPH at this power. Your surveyor should create a fuel burn chart for you that will give you good baseline on the whole drivetrain at various RPM.

I also agree with using Tony Athens. I'd sign up for an account on boatdiesel.com so that you can get full use of that site. Tony used to be a big contributor there, and his writings are still there.

From my experience, the QSC is a great motor, but here are couple of things to watch. The Sherwood pumps tend to eat impellers. I changed them every 2 years and often found some breakdown. There is a good writeup on the QSC-500 thread on this board on how to change them (pulling entire pump off is easiest way, and that is what I did). Watch the drive belts, for some reason the QSC wears them out quicker than normal. Easy job to change them (again refer to instructions on the QSC-500 thread). I found the OEM belts found on sbmar.com lasted longer than the aftermarket ones. Keep up on fluid / filter changes and buy a K&N cleaning kit to annually clean the K&N air filters. Managing the diesel fuel is also very important and you should refer to Frank Webster's writeup on this. Lots of other little things, but overall these motors are very easy to maintain yourself, and the ER has good space to work, especially with the salon doors open. I can send you a spreadsheet of my schedule, if you want, let me know. Good luck.
 
sb in gp said:
Agree with Islandtime. Watch the load on the motors and keep it at or below 80%. Cruise speed on my last boat, which was same year and motors as yours, was about 2300. At this power, depending on weight on board I would cruise at about 23-24 knots and the load was less than 80%. You'll be burning about 34 GPH at this power. Your surveyor should create a fuel burn chart for you that will give you good baseline on the whole drivetrain at various RPM.

I also agree with using Tony Athens. I'd sign up for an account on boatdiesel.com so that you can get full use of that site. Tony used to be a big contributor there, and his writings are still there.

From my experience, the QSC is a great motor, but here are couple of things to watch. The Sherwood pumps tend to eat impellers. I changed them every 2 years and often found some breakdown. There is a good writeup on the QSC-500 thread on this board on how to change them (pulling entire pump off is easiest way, and that is what I did). Watch the drive belts, for some reason the QSC wears them out quicker than normal. Easy job to change them (again refer to instructions on the QSC-500 thread). I found the OEM belts found on sbmar.com lasted longer than the aftermarket ones. Keep up on fluid / filter changes and buy a K&N cleaning kit to annually clean the K&N air filters. Managing the diesel fuel is also very important and you should refer to Frank Webster's writeup on this. Lots of other little things, but overall these motors are very easy to maintain yourself, and the ER has good space to work, especially with the salon doors open. I can send you a spreadsheet of my schedule, if you want, let me know. Good luck.
Click to expand...
I second all of this. I just replaced my impellors for the first time in 400+ hours on the 06 and was really surprised by the condition they were in. The port impeller had some cracking and scoring but I had a brain fart last season and inadvertently ran for about twenty minutes with the seawater valve on the port engine in the off position. I actually went to WOT during a sea-trial and it wasn't until then that the temp on the port engine broke from the starboard. I ran another 50 hours before changing it.
Overall I am really impressed and happy with the QSCs admittedly though they are my first Boat Diesel engines I've owned so I don't have anything to compare to. I read every thing I could though before making the plunge and everything I read reinforced my comfort in going with a Cummins powered boat.
Carpe Diem
 
Islandtime04 said:
I have an older generation of the 8.3 and the 500's are common rail so you'll have better efficiency. (I always laugh when we talk efficiency on boats). Actual speed and consumption varies +/- 1-3knots based on many factors (current, weight, temp, fouling levels, etc.), but generally I cruise between 20-23 knots. 2250rpm seems to be the sweet spot for me. That's about 80% load burning 32-34/gal.hr. Others on this thread with your exact engines may have other thoughts.
Also recommend bookmarking Tony Athen's site.
https://www.sbmar.com/engine-info/cummins-qsc-specifications/
Click to expand...
Thank you, and yes, just bookmarked the link!
 
sb in gp said:
Agree with Islandtime. Watch the load on the motors and keep it at or below 80%. Cruise speed on my last boat, which was same year and motors as yours, was about 2300. At this power, depending on weight on board I would cruise at about 23-24 knots and the load was less than 80%. You'll be burning about 34 GPH at this power. Your surveyor should create a fuel burn chart for you that will give you good baseline on the whole drivetrain at various RPM.

I also agree with using Tony Athens. I'd sign up for an account on boatdiesel.com so that you can get full use of that site. Tony used to be a big contributor there, and his writings are still there.

From my experience, the QSC is a great motor, but here are couple of things to watch. The Sherwood pumps tend to eat impellers. I changed them every 2 years and often found some breakdown. There is a good writeup on the QSC-500 thread on this board on how to change them (pulling entire pump off is easiest way, and that is what I did). Watch the drive belts, for some reason the QSC wears them out quicker than normal. Easy job to change them (again refer to instructions on the QSC-500 thread). I found the OEM belts found on sbmar.com lasted longer than the aftermarket ones. Keep up on fluid / filter changes and buy a K&N cleaning kit to annually clean the K&N air filters. Managing the diesel fuel is also very important and you should refer to Frank Webster's writeup on this. Lots of other little things, but overall these motors are very easy to maintain yourself, and the ER has good space to work, especially with the salon doors open. I can send you a spreadsheet of my schedule, if you want, let me know. Good luck.
Click to expand...
Thank you for the detailed and useful information. I would love to have a copy of your schedule if you are offering. A little anxious on the diesels, but also excited!
 
Carpediem44DB said:
I second all of this. I just replaced my impellors for the first time in 400+ hours on the 06 and was really surprised by the condition they were in. The port impeller had some cracking and scoring but I had a brain fart last season and inadvertently ran for about twenty minutes with the seawater valve on the port engine in the off position. I actually went to WOT during a sea-trial and it wasn't until then that the temp on the port engine broke from the starboard. I ran another 50 hours before changing it.
Overall I am really impressed and happy with the QSCs admittedly though they are my first Boat Diesel engines I've owned so I don't have anything to compare to. I read every thing I could though before making the plunge and everything I read reinforced my comfort in going with a Cummins powered boat.
Carpe Diem
Click to expand...
Same here, trying to learn as much as I can before pulling that baby out for the first time! Thank you for the information!
 
Tomco said:
Smart idea to put it at the junction of the chambers. Seems most everyone who have opened it up has had water! Will do mine in the spring and see …

It turns out that when I vacuumed out the water from the area, there is about a 1.5 inch gap at the bottom of the lateral bulkhead under the hole I cut so all of the water was able to be evacuated from the aft section after all. No need to cut additional holes or center the hole over the bulkhead intersection.
Results may vary as it looks like the pic that Bennett posted and drawings show the bulkhead/formers extending to the hull making three sealed chambers.
Rusty
Click to expand...
 
Tomco said:
Smart idea to put it at the junction of the chambers. Seems most everyone who have opened it up has had water! Will do mine in the spring and see …



It turns out that when I vacuumed out the water from the area, there is about a 1.5 inch gap at the bottom of the lateral bulkhead under the hole I cut so all of the water was able to be evacuated from the aft section after all. No need to cut additional holes or center the hole over the bulkhead intersection.
Results may vary as it looks like the pic that Bennett posted and drawings show the bulkhead/formers extending to the hull making three sealed chambers.
Rusty​
Click to expand...
 
Fuse box? Never noticed the red light before - it’s on the back transom of the boat next to the fuel filter for the generator. Any idea on what this is?
fuse?.jpeg
 
sb in gp said:
Agree with Islandtime. Watch the load on the motors and keep it at or below 80%. Cruise speed on my last boat, which was same year and motors as yours, was about 2300. At this power, depending on weight on board I would cruise at about 23-24 knots and the load was less than 80%. You'll be burning about 34 GPH at this power. Your surveyor should create a fuel burn chart for you that will give you good baseline on the whole drivetrain at various RPM.

I also agree with using Tony Athens. I'd sign up for an account on boatdiesel.com so that you can get full use of that site. Tony used to be a big contributor there, and his writings are still there.

From my experience, the QSC is a great motor, but here are couple of things to watch. The Sherwood pumps tend to eat impellers. I changed them every 2 years and often found some breakdown. There is a good writeup on the QSC-500 thread on this board on how to change them (pulling entire pump off is easiest way, and that is what I did). Watch the drive belts, for some reason the QSC wears them out quicker than normal. Easy job to change them (again refer to instructions on the QSC-500 thread). I found the OEM belts found on sbmar.com lasted longer than the aftermarket ones. Keep up on fluid / filter changes and buy a K&N cleaning kit to annually clean the K&N air filters. Managing the diesel fuel is also very important and you should refer to Frank Webster's writeup on this. Lots of other little things, but overall these motors are very easy to maintain yourself, and the ER has good space to work, especially with the salon doors open. I can send you a spreadsheet of my schedule, if you want, let me know. Good luck.
Click to expand...
And oil sampling/analysis before each oil change on the engines, gears, and generator. The oil analysis is a condition and trend analysis to understand wear, contaminates getting in the equipment, fuel burn performance, and a host of other indications that allow early detection to avoid what could be very costly repairs.
 
JoAna said:
Fuse box? Never noticed the red light before - it’s on the back transom of the boat next to the fuel filter for the generator. Any idea on what this is?View attachment 79175
Click to expand...
It looks like an add on. I’ll check to see If I have one but I don’t remember ever seeing one there. Should be easy enough to follow the wires to see where it goes. Either that or remove a the fuse and see what stops working.
Cheers
Carpe Diem
 
Carpediem44DB said:
It looks like an add on. I’ll check to see If I have one but I don’t remember ever seeing one there. Should be easy enough to follow the wires to see where it goes. Either that or remove a the fuse and see what stops working.
Cheers
Carpe Diem
Click to expand...

Thinking the same...I do not have either....

Bennett
 
Speaking of curious electronics. What does the "elect" switch located at the bridge switch panel control?
 
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