Big Decision Time

[Bob Bradley]

I'd install QSMs at 660 hp. (they do come with higher ratings, but you can probably get 660hp on the reman program which is definitely the way to go on an older boat) I'd suggest T&S Marine Engines in Crisfield, MD, as the place to buy them. You might be able to get the install done in that area, too.

With those engines, your boat will be substantially faster, burn less fuel, and outlast you. Which a Hatteras will do anyway; they will outlast all of us.

The downside is that you will miss at least part of a season, but if you hauled the boat in the fall, you might get in the water for sea trials by spring.

The reman approach is a good idea. My biggest worry is overpowering her too much. I've heard horror stories about the keel walking problem and I don't want to have to deal with experimenting with cutting the keel.

[Bob Bradley]

We have a neighbor with an 86 43 with Cats. Faster, quiter, and now the second generation family members are using the boat too. Short version, they use it all of the time.
Since you like to fish, Repower and enjoy it as long as you can. It will probably make you smile.

The passion of ownership shines through your post. Have fun.

Do you know which Cats? Model and HP?

[Avenger]

The reman approach is a good idea. My biggest worry is overpowering her too much. I've heard horror stories about the keel walking problem and I don't want to have to deal with experimenting with cutting the keel.

Watch the talk from the Hatteras engineer. Don't worry about keel walking.:

https://m.youtube.com/watch?v=dirBIsgblt4 Right around the 20 minute mark.

From https://www.samsmarine.com/forums/sh...1-convertibles

[rsmith]

Don’t do it. I know your type fishing mission better than anybody. Overnight offshore you really need a 50’+ boat with ample fuel to stay and fish. The best thing we did was buy the 50. 1000 gallons of fuel 2 generators plus the extra space and comfort when things got snotty we could stay in weather everyone else ran from. August 23 1980 we put 9 swords on the boat. We were the only boat at the poor mans canyon because everyone else ran for home.
Plus how valuable is your time at this point of your life? Repowers take not just money but time and aggravation. I don’t care what anyone says nothing goes smoothly there are always problems. One of our former members here repowered his 52 with qsm11’s and had bad vibration issued that the installer could never solve. Last I talked to him he lost 2 seasons and was thoroughly disgusted. Buy something bigger that’s already running with all the bugs worked out. And get rid of the bladder!

[Avenger]

BTW, the physics says that 660 HP vs a 48,000 lb boat will top out at about 25 kts with everything else being optimal. How much does she weigh with a normal loadout?

[Cricket]

So, being one of the few that has gone down the repower path I understand both sides of the decision.
I do agree with Scott that the 43 really is a little small to be doing your type of canyon trips. Think you would find them much more enjoyable not having to deal with taking extra fuel in a bladder and also the better sea keeping of a larger boat.

But, when you have your boat the way you want and need it to be and the only thing wrong are the engines I say go for it.
Our 8v92's almost ran us out of boating because they just had become unreliable, now it's 20 years after installing the CATS and they still run like the day they were installed.

Might want to look into the CAT C8.7 which is in the mid 600hp range. Remember I'm a believer in having as much HP as will fit and you can afford and then running them at lower RPM's for longevity.
As far as "keel walking" goes that's just a myth, it's a suction issue that can easily be corrected for very little $$$, as posted earlier.
Our boat does get a little wonky when it's light on fuel and in the 27-28k area, we recently tried running it with a rope tied from spring line cleat to spring line cleat and the result was amazing.
Now we just need to figure out were to add the batons on the bottom over the winter.
Only has taken us 20 years to get to figure this out..........

[bluedart73]

My two cents ( disclaimer: I don't own this big a boat) but if the repower will need new gear boxes and controls, I would go for much larger engines. Look at the 45-50 Vikings and see what they are putting in these size boats.

Not that you are going to go the 40KNTs of a new boat but the extra power (with the 48k weight) is great in heavy seas and going out with a full load. The boat will "loaf" along rather than "lumber".

48k is pretty heavy.

If you repower (underpowered) you will be a very unhappy camper after a very significant
investment. I think that is why a lot of recent repowers are on the market.

You may also need to look at how large a prop you can clear with the current struts and shafts.

[Dan Mapes]

New motor dialog aside, those 6v92's sound ok but the desire for a new engine and some performance is beating a path to your wallet. Are you really going to be able to forego the bladder on the bow?

Sixty five is a good point in life. All things considered would it be that way in 5 to 10 years? As said before 1 or 2 may go into the bin because of the work on the boat to upgrade. If it's all working now I have to ask why bother?

Are those two years worth it? "This ain't no rehearsal".

Here is an example of what you are looking at ->

https://www.yachtworld.com/boats/1979/hatteras-43-convertible-3196186/

If you are close by perhaps a trip to take a look might be a good idea.

[jim rosenthal]

I would rough guess that you'll spend 125K, perhaps more, to repower your 43 with QSM11s. They DO burn less fuel- it's possible you might not need the fuel bladder.

At the end of that process you'll have brand new engines (even the remans are new) plenty of performance, better economy, and years of fishing ahead of you. But you'll have to keep the boat to get the value out- not all of it, I suppose, but enough to make you happy.

If the rest of your boat is sound, I'd just repower her.

Incidentally, one of our forum members, Captain Coop, had his 45 Series 2, a similar hull, repowered with M11s and she hit over 34kts on trials. Not fully loaded- could have taken a bit more pitch in the wheels. So yours should feel quite sporty when you're done.

CAT makes some decent engines, but in this segment of the market, I think the M11s are the preferred powerplants. Which means if you ever DO decide to sell and buy a bigger boat, you'll get a little more for the current one.

Also, 6v92 cores are not valueless- sell them in B&H and get yourself a few bucks back.

[SKYCHENEY]

The QSM11 has dry manifolds and turbos. This has caused some issues in some boats with warped manifolds and sooting. If propped right to keep the heat down at certain RPM, they are said to be okay. But, I would prefer an engine with water cooled manifolds and turbos. The heat in the ER would be less and less chance of fire.

The Cat C12 was produced in a compact model that might work. Don't just look at HP, its the torque that matters. Don't go with fast turning engines that run 3000 RPM. The torque will not be sufficient.

Which model Scania are you considering? Cat and Cummins would obviously provide the most service locations but that may not matter if you fish out of the same area all of the time anyway.