Hi everyone, I'm currently considering the purchase of a 1995 Viking 50 Convertible, powered by twin MAN V12 1100 HP (2842LE402). The engines have around 3000 hours, with a major overhaul done at 1000 hours in 2010. Since then, annual routine maintenance has been carried out by the same owner. The boat is located in Europe, where there’s not much experience with these models, so I’d really appreciate your input on a few points: 1. Should I be concerned about the 3000 engine hours on these mechanical MAN V12s? Any typical issues or weak points I should check for? 2. Do Viking hulls from the '90s have any known structural issues? I read that Viking had some problems with lamination or hull blisters in certain years—does that apply to this model? 3. Does anyone have real-world performance and fuel consumption numbers? A rough table like this would be super helpful: 950 rpm – 7.5 knots – 7 gph (total) 1300 rpm – 10 knots – 12-14 gph 1800 rpm – 17 knots – 28-30 gph 2000 rpm – 21 knots – 36-38 gph Any advice, experience, or numbers you can share would be greatly appreciated! Thanks in advance!
I had a 98 58 with v12 1200hp mechanical mans. The 50 with 1100s should be a rocketship but seems like the engine room would be tight to the extreme. Here were my numbers, I’d guess the 50 will be a little faster with similar fuel burn except at/near WOT where it would be less: 800-900 - 10-13gph, 8.5kts @800-900 1000 rpm - 15gph, 9.5kts 1800 - 62 gph 19.5-22.5 kts 1900 - 71 gph 23-24 kts 24/71=0.338 2000 rpm - 85 gph 25-26 kts 2100 - 94 gph For a 30 year old boat I personally would rather see more hours on the engines than less. So I wouldn’t worry about the hours. Those mans will run for infinity with proper care. But keep in mind proper care is very expensive. Every 2-3 years/1000 hours requires a pretty expensive maintenance interval including injectors. Injectors are $1k a piece in the US and you’ll have 24 of them. I spent $200k+ over 2 years maintaining and fixing those engines and none of that included a rebuild. Maintenance, gear oil cooler ($10k if you can find one), 4 turbos, damper, injectors, etc.
I've only just seen this post after replying to your other thread where you said you're looking at a Viking 50 powered by a MAN 1050hp. Are you possibly looking at two different Viking 50? Anyway, in spite of the smallish output difference, the V12/1100 and the V10/1050 are very different beasts. I already commented on the latter in the other thread, while the former is more akin to the V10/820.
If you don't mind me asking, which max RPM/speed can you reach? 25/26 kts @2000 rpm suggests that the boat should reach the low if not the mid 30s @2300, which is the max RPM those engines are rated for and the boat should be tuned for, with the right props/conditions. If anything, with MANs it's actually better to prop the boat for a bit more RPM rather than less, which could make them run a bit stressed.
I had it propped to make 2350. Id run it up to WOT briefly a few times a year to make sure everything was ok. Seems like it was about 29-32kts, but I never actually cruised at that speed so I don’t have an average recorded. 2150 was the highest rpm I cruised at, was about 27kts and about 100gph but I didn’t do it a lot, so I don’t have an average recorded there either. 1950 was generally where I ran it.
I see. Makes good sense, of course cruising at WOT is never a good idea, unless with engines rated as continuous unrestricted - which the MAN models we are debating definitely aren't, being all "light duty" rating, in MAN jargon. For which, 2000 is what they recommend, with up to 2100 "tolerated" but not for ages. My question was purely out of curiosity about the progression of rpm/speed, thanks for your clarification.
I run a 58 with a very tall tower. 1100 MANs. We run at 1800 and burn about 65GPH but doing 24 kts. New clean bottom, we can get another knot or 2 at the same RPM
Look up any propeller curve chart for fuel burn at each RPM and that's what you'll burn. The 1100's burn 86 gph for both at 80%. I managed a 50' Viking with 1100 mans a long long time ago and the boat was really fast. Hard top, no tower, ran 38+ knots at 80% load. MAN recommends 80% load as cruise, if they're propped to achieve 2300 rpms WOT full fuel/water. RPM's at 80% load vary greatly depending on how much water and fuel you've burned off. MAN's like to be run at 80%, not 60% load..........
How could you tell the load? The 1100 MANs the OP mentioned are 100% mechanical (same as mine), and if you are aware of any method for knowing at which load they are running, I'm all ears.
The boat I managed was 2001 or 2000, this was back in the mid 2000s. At cruise it ran 38 knots, could have been by RPM or could've had the small man LCD displays I cannot remember. I just do remember that boat was very very fast for it's day and that's what it ran. I also remember that it rocked very easily while at the dock.
Mine were all mechanical as well with no floscans or anything. I logged every RPM I ran at and for how long. Then I totaled up estimated fuel burned based on the curves. When I filled back up again, I compared actual burned fuel vs calculated. I got to where I could routinely estimate fuel remaining with an accuracy of 20 or 30 gal on over 1000 gal burned. Not only does this provide confidence in fuel remaining (analog gauges are pretty worthless other than a very rough guide IMO), but it also gives you an indication of how close to the burn/load curve you are running. If you are over propped/over loaded, you’ll burn more fuel than the curve indicates at a given RPM. If you are under propped, you’ll burn slightly less.
