1988 48 hatteras convertible repower

[Captain Ralph]

What is everybody's thought on cummins qsm 11s at 715hp in the 48 hatteras I might be able to get my hands on a pair of them with gears for a good price

That 11L engine is great. Another fantastic truck engine.
Fore marine use, Cummins Frankensteined an exhaust header/manifold.
It is not water cooled.
Special care was given to keep that exhaust manifold temp down.
Just recently, a water cooled manifold is now used. I have not been around this model yet.
I do not believe this newer manifold is available to update the older 11s.

It is a tall and wide beast. You will need a down angle clutch.

Lots of good notes like this one on Tony's web site.
https://www.sbmar.com/articles/the-c...-engine-story/

[Scarlett]

I’ve been watching some videos by Diesel power pro where they are putting together Detroit long blocks. Has anyone repowered with one of these. Looks like an 8-71 is about $24,000. Also as far as Nani goes in the past they had problems with their cooling systems. Not sure if that is still a factor but in the ‘80’s they all but disappeared because of the cooling problems.

[Captain Ralph]

Like Jim had mentioned, Cat 3406s would be something to look for.

I luv that beast and it will make the horsepower you were looking for in post #1.
It is tall and with on end H/E,, long.

I always wanted to replace my 12V71TIs with the 3406E.
20 years later, our 12s are still BZ and hard to justify their replacement.

[captcrunch]

The qsm 11 if propped right and I believe burns 21gph or less per engine is good.

[jap201]

As mentioned, due to the exhaust manifold issues, you really can't use all of the 700hp. I think the safe rating is around 400 (450?)'sh hp out of that block due to warping of the exhaust manifold. I love cummins, but go to boatdiesel and do some reading on that particular engine. Listen to what Tony Athens says.

The cat's might be a better option for your boat.

Hopefully Bob chimes back in here on the 700hp qsm, he's done plenty of research on the qsm's

[hoodie55]

I would gladly go with the cat 3406E does anyone know who would have them laying around also thought about the c15

[madhatter1]

I repowered our 34 with new Cummins in 98. Was $56K and boat while nice, not worth that much. But since we planned on keeping the boat it was worthwhile. If you love the 48, plan on keeping it for a loooong time, and love the boat, yes it can be worth it. It will be very expensive and take longer than you would think. As others said many other items come into play as well as much fabrication on the fly.

Again, only worth it for the love of the boat and the plan to keep it and enjoy it for a very long time. I'm dumping oodles into my 46 which to some wouldn't make sense but this is my last boat until I am regulated to sitting in the cockpit of the 34 as my kids get me out on the water in the later years.

[riverrandy]

Id be happy to get you specifications and data on Scania Repower projects am involved with. We finnished a 53 Hatteras Convertible. The Scania DI13 800HP is the perfect v8-92 replacement in my opinion.

[madhatter1]

I would also like to add that given the current prices of new boats that even if overplayed on initial price of vessel and high price of the repower overall bang for the buck is still favorable. If you ignore resale value if you have to get out before realizing the gains of the repower. Still cheap by those standards. So if goal is to keep it and run it only real “danger” is change of plans due to life circumstances and then so what? Just deal with life.

To me biggest concern is cramped engine room. Make sure things will fit and be serviceable.

[hoodie55]

I bought the boat for next to nothing it needed a little work the interior is all brand new I did new floors new windows new saloon door I built a new helm console for the boat I am in the process of re painting the entire boat the hull will be kingston gray and the topside will be snow white the only thing left to do to the boat is rebuild the 8v92's which the prices I have gotten are people who will do it but they don't want to or repower I have a pretty good deal on nanni 900hp engines and I can de rate them to 800 hp they are the same block as the scania or I could go volvo d11 at 725 hp or d13 at 800hp aside the problem I am running into with the nannies is that there are service distributors around me but there aren't enough of those engines around for them to really carry anything for them so if I had a problem I would have to get the part from Massachusetts area which the dealer I talked to said he wouldn't have a problem doing if I went volvo eckels marine diesel would I were I would get the engines and they would do the installs I can remove the old engines myself I have the equipment to do it I can do all of the engine room glass work myself also have done it before on other projects so I can save alot in cost I like cummins have had them on boats in the past just not sure if the qsm 11 are enough engine to get a 26 knot cruise that is the number I am trying to shoot for I may be over thinking it and the qsm 11s may get me there especially with the offset in engine weights the cat 3406 would be a great engine in that boat just have to be at the rite place rite time to get my hands on those babies.