Thread: Marinized 4BD

Originally Posted by roverrescue

I always keep an eye on the zuzu happenings on this site, so it was with much pleasure when I pulled the covers off one of the engines in the engine room of a still being constructed 15m cat this arvo. Its a beast of a cruising ship, near enough to 5m wide. 3 double births, huge galley and bathroom, awesome upstairs area... cheap too!!!!

Anyway, unsure of specific designation but the ship runs a pair of Isuzu 4BD (somethings) Turbo. Each putting out 110hp through a hydraulic clutch pack to a shaft drive with 20" propellor. The two donks are fed from a 3000L tank and at a cruise of 14-16kn it has a crusing range of 1500nm. (Thats Cairns to Darwin)

Interesting Points:

Brand new Price circa $40k each with salt water to coolant cooling system and including hyd gearboxs.

They are mounted on those flash hydraulic engine mounts.

The engines are fit in place and then the engine room built around them.
Reliabaility! they dont ever come out. Or as Kurt the builder says if they need a rebuild. Strip the head and ancillaries off then muscle the block out the door.

And what else but an isuzu 15kVa gennie for aux power to the vessel.



Anyway, I can dream.
Steve

Hmmm, would want to do some pelvic floor exercises after that number of offspring, 3 lots of twins!!



Sorry Steve, couldn't resist that one

JC

They do a 4BG1T marinised with about 200hp.
If you ever get the chance to get a parts list for that engine, let us know. The pump, injectors and turbo numbers would be of great interest.

Originally Posted by roverrescue

The engines are fit in place and then the engine room built around them.

Reliabaility! they dont ever come out. Or as Kurt the builder says if they need a rebuild. Strip the head and ancillaries off then muscle the block out the door.

Sounds a great project. The beauty of cats that size is they don't necessarily need huge engines to move them at cruising speed.

I have never seen Isuzu's used in boats before, but having the heat exchanger using sea water cooling is standard practice. You get lots of different truck engines, including Commers (but they tend to suffer from over heating due to the oreintation of the pistons).

Building the vessel around the engine is normal. It is far easier to do that than to build the vessel and then try to get all the plumbing, wiring, etc. into the vessel after. Engines are a pain the a*** to get in and out of boats at the best of time so doing it that way saves time, mess, and ruining carefully built boat bits if it slips while installing.

Thanks, interesting read

Alan

Regarding cooling, my gut feeling is that with twin diesos deep in the cat I would have thought hull cooling may be a little more reliable in regards to long range cruising. Bloody impellor housings, impellors, strainer baskets, pickups and rusting exchangers drive me nuts on the two smaller diesel boats Ive played with worked on. A 9m platey with 6 cylinder VOLVO slug and 20' Arvor with the little NANNI diesel somewhat akin to a 300tdi.

Both applications would physically fit the above said 4BD, not sure of weight and in the Arvor's case it would nearly double the output...

S

You're not wrong there. I personally prefer keel cooling but then I prefer displacement hulls too

On higher performance hulls the addition of external piping on the hull adds significant drag, which is why they nearly always have through hull fittings and pick-ups.

The Nanni seems a good little unit. Reasonable price and quiet, which is important on most boats where engine noise can be a real problem. Big horsepower is not always a good thing on any vessel. It is better to have a smaller unit that pushes the boat at the correct hull speed using 85%-or-more of its available power than to have a more powerful engine that is being under utilised. Better for fuel economy, power-to-weight ratio, and engine wear.

One of the local boat traders was doing the Arvor's. I quite like the design as a general purpose vessel, but they tried to target the small commercial fishers in NZ. Unfortunately they were 20 years too late since the small boat fishing industry no longer exists after the introduction of quotas in the 80s. They missed the pleasure market too, their marketing wasn't good enough.

Alan