repower my old Hatteras

[mfacchinetti]

dear all sorry for my poor english... my name is Matteo i own an old 50" hatteras dated 1981
that run with 2 detroit 8v
i amrestaurating this boat and I'm evaluating to repower it with a couple of new engines , does
aanyone know the maximun horsepower that this boat can accept? , i have a good deal with two cat c 18 1100 cv
but i am seriously worried about the consequences i dont think that is this Hull structured for hier
speed ? does anyone of you have a direct real experience on this hull Thanks a lot for your precious indication best regards Matteo

[Fanfare]

Your best deal is to rebuild the Detroit Diesel 8V-71 natural (no turbocharger) engines. These are rated at 350 horsepower and will last forever. Mine were too old to be retrofitted with turbochargers because the engine block could not handle the increased need for cooling.

I replaced my engines and transmissions 20 years ago with Detroit Diesel 6V-92 TA engines. each at 550 hp. This gives my 1966 50MY a top speed of 23 knots. For this horsepower I had to replace the transmissions, shafts and props. I have been very satisfied with this, which was recommended to me by Jack Hargrave, the boat's designer. Thus I know this much horsepower is safe. I did not have to modify the engine stringers. Mr. Hargrave cautioned me to not try Detroit Diesel 8V-92 engines as he said they would not fit in the engine rooms.

For much greater horsepower you will have to use larger shafts. This is possible, but by then you will have spent more than rebuilding the old engines. Your Allison model M transmissions cannot take much increase in horsepower.

Good luck with your boat. It is a great design. I have had ours for 47 years and am still pleased.

[saltshaker]

I believe he has a 50C with 8V92TI's. The C18's will fit nicely but you'll be redoing all the running gear too. There are a few 52C's with the 3406's, which are the same block as the C18's. I think you'd be pooring way too much money into that boat. If it were a 52C you'd be better off but the 50C II is a bit light on cockpit and running surface aft. If the rest of the boat is perfect or if you are planning a complete custom refit then go for it as long as you plan on keeping it forever. She would be fast indeed.

[mfacchinetti]

Thank you very much for your precious suggestion. This mach my mechanical suggestion i will keep you posted ciao matteo

Your best deal is to rebuild the Detroit Diesel 8V-71 natural (no turbocharger) engines. These are rated at 350 horsepower and will last forever. Mine were too old to be retrofitted with turbochargers because the engine block could not handle the increased need for cooling.

I replaced my engines and transmissions 20 years ago with Detroit Diesel 6V-92 TA engines. each at 550 hp. This gives my 1966 50MY a top speed of 23 knots. For this horsepower I had to replace the transmissions, shafts and props. I have been very satisfied with this, which was recommended to me by Jack Hargrave, the boat's designer. Thus I know this much horsepower is safe. I did not have to modify the engine stringers. Mr. Hargrave cautioned me to not try Detroit Diesel 8V-92 engines as he said they would not fit in the engine rooms.

For much greater horsepower you will have to use larger shafts. This is possible, but by then you will have spent more than rebuilding the old engines. Your Allison model M transmissions cannot take much increase in horsepower.

Good luck with your boat. It is a great design. I have had ours for 47 years and am still pleased.

[mfacchinetti]

I believe he has a 50C with 8V92TI's. The C18's will fit nicely but you'll be redoing all the running gear too. There are a few 52C's with the 3406's, which are the same block as the C18's. I think you'd be pooring way too much money into that boat. If it were a 52C you'd be better off but the 50C II is a bit light on cockpit and running surface aft. If the rest of the boat is perfect or if you are planning a complete custom refit then go for it as long as you plan on keeping it forever. She would be fast indeed.

Dear jack. Thanks a lot ,i will evaluate this second option but for sure you are right if i spend all thos money i will keep it forever ...