- This topic has 1 reply, 2 voices, and was last updated 4 years ago by
.
-
Topic
-
Hi gurus –
I’m comparing two boats right now, and am hoping for some feedback on engines.
Both boats displace about 65,000 pounds and are single screw. One has a QSB5.9 330. The other has a QSL9 330. They are both 2007 boats, and each of them has around 2,500 hours of operation.
Assuming that the maintenance has been equivalent on both boats (which is not necessarily the case, but indulge me in that assumption for the time being), what are the practical differences between the two engines? Does the QSL have any significant advantages over the QSB, or vice versa?
Thanks in advance!
-
The 2 engines should NOT be compared in anyway shape or form.. It would be like comparing a Chevy Silverado 1500 to a HD 3500 trying to move 50 ton’s of concrete from one job site to another…
Comparisons below are based on a SEABOARD Proper set-up and maintenance from Day One.
The QSB 5.9 is a 2800 RPM 330HP engine with a realistic cruise power in a vessel like this of about 150 hp at on about 2100 RPM .. The engine is a parent bore 5.9 liter engine built to world class standards, but it’s still a 5.9 Liter engine…. Assuming 50% of the vessel operation was done at this load, and the other 50% of the hours were at less load levels , you could expect about 30,000-40,000 gallons of fuel run thru this engine before it would need rebuilding from being “wore out”..
The QSL9 is a completely different animal.. Just under 9 liters, mid-strop wet liners , 2-piece steel topped pistons, roller cams, etc etc, and develops 330 BHP at 1800 RPM and is designed to run at full power 6 out out every 12 hour duty cycle………….Assuming you need the same 150 HP in this vessel to get your “magic vessel cruise speed” ( 7-8 kts-ish), this engine will do this 24-7-365 at 1350 RPM burning the same 7.5 GPH the QSB would. Not that this really matters, this engine can make 1145 ft lbs of torque at 1400 RPM if asked to…………….Seeing 100,000 gallons of fuel burn on this engine would be a start.. I watch over a few now that are in the 150,000 gallon range and run “as new”..
IMO, the QSB 5.9 is a great engine but is really not suited for a vessel of this stature. Maybe a single engine 30-40 Ft / 20,000- 30,000 lb trawler. If you really needed 300++ HP for any length of time (like to make a 50-100 mile move) in a vessel this size, it would not be up to the task regardless of what what else you read of have been told.
You can find power curves on this web site.
Tony
2 users thanked author for this post.
You must be logged in to reply to this topic.