Hull Thickness & New Stabilisers 1984 61MY

[scottinsydney]

Today I hooked up the oil cooler oil hoses to the tank and the 1/2" cooling water hoses. The cooling water is from an offtake on the starboard engine Jabsco raw water pump elbow. Quite a crafty way to extract water.

It would appear that the old stabiliser system probably never had any oil cooling as the old water hose run was up to the ceiling and over to the old stabiliser tank. In testing I found that the head pressure was too much for the Jabsco offtake at any RPM. No water flowed.

Rerouting the hose to engine level now produces a nice flow of raw water through the oil cooler. Tomorrow I install the new Vickers hydraulic pump to the rear of the motor and turn the hydraulics side on for the first time.

I'll have oil rags everywhere because as an Australian Prime Minister once said "Life was not meant to be easy."

[Pete]

Do I understand the setup correctly? A portion of the water formerly flowing to the main engine heat exchanger is being diverted to the stabilizer oil cooler and then overboard? If so, would it not be a better solution to pick off a divert point just before the exhaust spray head to cool the stabilizer oil. My experience and understanding is the cooling systems on DD need all their cooling water if not more to maintain their operating temperature. First step would be to get the spec on just how much cooling the stabilizer oil needs and also measure the temperature of the spray head water that is available. At very least consult DD about the setup.

Just MHO.

Pete

[kelpy]

Picking up the cooling water just after the pump is the correct location to do so.

[krush]

At very least consult DD about the setup.

Who would he consult at DD?

[scottinsydney]

The Jabsco offtake was installed back in 1984 when Hatteras of Ft Lauderdale completed the boat. When I bought the boat in 2015 the water hose ran up the wall and across the ceiling to the old stabiliser system. I did not know if the offtake worked so I disconnected at the offtake and ran a new hose to a garbage bin. The flow at 750rpm was about 4 gallons a minute.

But it did not flow via the ceiling hose due to the height. . Lowering the hose to the height of the offtake and positioning the oil cooler at the same level produced a good water flow. Today I double checked everything mounted the Vickers pump and started it all up. Oil flowed, tank level fell proving oil was circulating and pipes vibrated as system was purged of air. Only one small oil leak and that fitting was nipped up. This tested the pump, tank, water flow and oil cooler. There is a solenoid on the tank when when turned on will allow oil to flow to the actuators. You turn this solenoid on when you are about to use the system with fins installed.

So today was a half test of the hydraulics, albeit a great step forward. The reason I used the old water offtake was that it was preinstalled. I would never have thought to do that. Lowering the height of the hose has made the offtake functional. I've checked all the temperatures on the various fittings and components and oil was not really getting warmed by the circulation, but was being cooled anyway by the cooler.

I oversized the cooler I'm told about 3 times to 12" long body x 3" wide diameter. Photos show Vickers pump attached with ball valve just before pump. And photo of the Jabsco elbow offtake.

[jim rosenthal]

It looks like he's only diverted a small amount of the flow from the Jabsco pump.

[Pete]

Not sure if Hatteras of Lauderdale or Hatteras the OEM manufacturer of our boats had the smarter people, but for sure there was diversity.

Our 48 LRC came from the factory with Gyro Gale stabilizers which are pneumatically controlled versus hydraulically. Each engine has a twin cylinder air compressor that includes a cooler in the line before entering the air tank. These coolers are in the raw water flow between the exit on the engine heat exchanger and the exhaust spray heads, being placed there not rob any BTUs cooling water capacity from the engine heat exchanger.

Maybe there is no superior approach. But, the picture of the diverter looks like a non DD custom part by the installer.

As for another question, where to find a DD expert, I would start with an MTU current day mechanic, seek out an old, slightly overweight, grumpy looking one with lots of mileage apparent and ask him.

Pete

[kelpy]

i have never seen a nipple welded to the adaptor but that is the proper place to pick up your stabilizer cooling water cooling water. You will have plenty of flow when throttle up.

[Pete]

Kelpy, I am curious as to why you state with such certainty that the tap into the raw water output adapter is the "proper" placement for non engine cooling water. Also curious as to the path overboard for the oil cooler water.

Thanks

Pete

[scottinsydney]

The water leaves the oil cooler using the original hose and goes to the starboard wall and exits via a through hull side fitting just above the waterline. It looks like the installer connected the hose into an existing grey corrugated drain hose exit that comes down the outside wall of the engine room. I tested the flow up to 1000rpm at cruise yesterday. Lots of water is coming out.