Swapping Out Engines

[JCG]

I have purchased a 1975 46 foot HAT which I am restoring and would like to rebuild/replace the current Detroit 8v71TIs. I have found replacement engines from Diesel Specialist out of Baton Rouge. (anyone have any experience with these engines?) My problem is I dont see any way to remove them from the cabin. My guess is that you must remove the entire bulkhead forward of the fishing cockpit. If so what is the best approach? Or am I going about it all wrong?

[saltshaker]

I have a 74 46" SF that I repowered 3 years ago with Detroit 6V92 TA's. the 8V71's will fit through the door but you have to take off the manifolds, fuel coolers, boost coolers, etc.

Jack Sardina

[JCG]

So you strip them down and go through the door. How did you lift them out, position a small crane on the aft end of the boat and reach into the door?

How did your boat perform with the 8v71TIs vs the newer 6v92 engines? I am concerned that the boat will be on the slow side. Thanks for your comments.





/

[saltshaker]

The yard setup an A frame over the engine, lifted it, and then removed it using a large fork lift with a boom attached to it.

I had 8v71N's so I only cruised at 16-16.5kts and 19-19.5kts WOT. The new engines are 550HP 6v92TA's. I am a bit underproped but I still cruise 20-21kts @1950, 23kts @2100 and 26kts WOT. This is with full fuel, water, gear etc. My boat is also on the heavy side for a 46C. Previous owner added another layer of 5/8" plywood to the salon sole, all new wood covering the old walls, moved the galley up with new cabinets and island etc. This added a lot of weight.

If I had the right props I think I would pick up another 1-1.5 kts. I am happy with the speed and prefer to keep the load on the engines lower. I run 2400rpm fully loaded or light on fuel and water.

[Bertramp]

I always thought that by the time they were making 46s they were putting TIs in all of the boats. What is the difference in fuel consumption from the 871Ns to the 692s ..... and difference in speed ?
thanks

[saltshaker]

there were a few 46C's that were ordered with 8V71N's and I've also been told there were a few with Cummins 903's (I've never seen one of those). The 8v71N's burned around 24GPH @ 2100rpm and 16-16.5kts. The 6V92TA's burn around 38GPH @1950rpm and 20-21kts. Fuel burn is estimate only. I have flo scans but have not yet installed them.

Jack Sardina

[Red Hatt]

How much would you expect to pay for 46 hatt that needs a refit ? I have looked at some older hatts up north that needed a complete refit. Not only a complete refit but they were as dirty as they come and thaey were asking big bucks.

[tomrealest]

I think you have to pay less $100,000 and that's if the boat has some redeeming value like newer Gen, A/Cs, etc., etc.
I know one guy who paid $50,000 did all his own work and came outOK.Another guy paid $30,000, paid for a lot of work and might be OK. I paid $100,000 and I can see now that I will be upside down in the boat.

In hindsight (20/20), I would have been better off making low offers on nice boats until I could have gotten one at a decent price.

[Genesis]

All depends...

If you're buying an older hull with clapped out engines, you should take the price of majors out of it. You can't take the price of NEW engines out, since you wouldn't get that deal if the engines were in good order.

Its all a numbers game. Done right you have a boat that is every bit as nice as a new Cabo or similar of the same size, but at less than half the price.

How is that a bad deal?

[garyd]

When I put 6v92's into the 1986 41 hat. I considered many options. I finally felt that if the engines were fully assembled and ready to go, that would be ideal. We made a small jib for a crane truck made sure everything was save and secure and put them in the boat. No A frame, no pieces, the engines were whole ready to go. We cut the back bulkhead open and it was far easier to fiberglass two very small visible sections back into place.

If at all possible I would highly recommend this. The first engine took about 1hr 30minutes. The second engine took 45 minutes.

The engine room stayed nice and clean and the engines have performed excellent.

Have fun boating.

P.S. I do not know where you are located but I can put my hands back on the crane and the jib.