1988 48 hatteras convertible repower

[hoodie55]

Hello I have a 1988 48 hatt convertible I am looking at repowering the engines I have been thinking about using are the volvo d13 800 hp scania di13 in 800hp and the nanni n13 cr3 800hp would like everyone's opinions on these engines or if some one has repowered a 48 in the past there expertise. Thank you

 

[Boatsb]

What options will fit best. Length can be the issue. Also down angle and height.

Get a good dealer who can make it work. It's not a simple job.

 

[Bob Bradley]

Hello I have a 1988 48 hatt convertible I am looking at repowering the engines I have been thinking about using are the volvo d13 800 hp scania di13 in 800hp and the nanni n13 cr3 800hp would like everyone's opinions on these engines or if some one has repowered a 48 in the past there expertise. Thank you

I looked at the Scania motors in 2019 when I was considering repowering my '79 43C. I was just sick of dealing with the 435hp DD 6v92ta engines. I can't recall which model I was looking at but they were well under 800hp. Sticker shock got me boat shopping instead. IIRC, back then the total job (engines, gears, shaft replacement, and ER work) had the job north of $250k. My shopping landed me in a 1986 45C with Cummins QSM11s at 535hp. I'm very pleased with the decision to buy one already repowered. I'm now cruising effortlessly in the 21kt range and I top out around 29kts. At 21 my fuel burn is around 35gph combined. Big improvement on the 42gph at 17kts in the old boat. The Scanias did come very highly recommended by my DD guru here in CT. He likely has over 50 years experience on Detroits by the way.

 

[motoryacht lover]

I would not go with Volvo. I have a friend that is a Volvo dealer and they are very difficult to work with and the parts are very expensive. Last spring I was in a shop that was a Scania dealer as well as Cummins and MAN and I asked what he thought about the scanias and he said parts availability was an issue and this was last spring (well past covid).

 

[rsmith]

What he said. Repowering never makes sense. Every one is a custom job that as anyone who’s honest will tell you the cost overruns are significant and the success of the installation is dependent on the installers. Better to pay up and find one already done that you can test run. Plus the 48C was never a well received model. They have never brought the money a series 11 45 or 52c has. Like the series 11 50 also. I had a friend had a 48C he passed and I helped the sons sell the boat. It was 2012 but we basically gave it away for $36k 500 hours never fished and sat at the same yacht club in Vero beach all its life. Some of the legacy members here will remember it.

I looked at the Scania motors in 2019 when I was considering repowering my '79 43C. I was just sick of dealing with the 435hp DD 6v92ta engines. I can't recall which model I was looking at but they were well under 800hp. Sticker shock got me boat shopping instead. IIRC, back then the total job (engines, gears, shaft replacement, and ER work) had the job north of $250k. My shopping landed me in a 1986 45C with Cummins QSM11s at 535hp. I'm very pleased with the decision to buy one already repowered. I'm now cruising effortlessly in the 21kt range and I top out around 29kts. At 21 my fuel burn is around 35gph combined. Big improvement on the 42gph at 17kts in the old boat. The Scanias did come very highly recommended by my DD guru here in CT. He likely has over 50 years experience on Detroits by the way.

 

[Pascal]

I would prefer something with better parts availability and service. I ve heard good things about Scanias but they re not “mainstream” enough unless you have a reputable dealer nearby. Volvos are good but parts and service are a little mor expensive and harder to get

Doesn’t Cummins have something in the 700hp range? Their factory remans are fantastic value. Cat also has a factory reman program now. Worth looking into

Nowadays with chain supply issues domestic engines are a plus, assuming they haven’t outsourced. Last year we waited 4 months for an 16V2000 MTU crankshaft for the boat I run. It turned out it was made in India, shipped to Germany for inspection before arriving here.

 

[jim rosenthal]

Both Cummins and Cat have reman programs; Cat is new to the reman game, Cummins have been doing it forever.

The 48 convertible Hatteras was not a popular boat for Hatteras Yachts and they didn't sell many of them. If you've had her a long time and you are very happy with her, go ahead, but at the cost of a repower you will need to own and run the boat a very long time. When it's time to sell she will still be a model they didn't sell many of- although she may be the best one in the world. Food for thought.

A huge factor is the repower yard and their familiarity and comfort level with whatever engines you choose. For example, if they've done several jobs with Cat and Cummins engines, and none with FPT or Scania, that would definitely steer my choice. Also think about where you are and which dealers are close to you. You don't want to have your warranty-work dealer hundreds of miles away if you can help it.

Cummins have M11s in that range, but 700hp is at the top of what that engine produces, and there have been comments here (and elsewhere) talking about exhaust manifold failures on M11s. On a boat that size and weight, I would be looking at a 3406E or whatever the modern equivalent of it is- a C18, maybe?

 

[captcrunch]

I’m In the process of finishing a repower on my 1988 38c which is very similar. Most likely will need a down angle gear. I am putting in a pair of c9 cats that were running takeouts. You have several quality choices of motor options and I would include the fpt options as well. Aside from engine and gears, there is all the ancillary items. A lot of the things in the engine room (hot water heater, waste pump, AC compressors) need to be relocated as a lot of the newer engines are shorter but wider then the original Detroits, and many of these items it may pay to replace at the time depending on age. Then there’s always a lot of old wiring, old transducers that might as well be pulled and glassed at the time, etc.

 

[hoodie55]

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

 

[SKYCHENEY]

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

Go on Boatdiesel and read about them. They wouldn't be my first choice.

 

[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-cummins-qsm11-marine-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.