Who has connected their shaft seal supplies

[Patriot]

The pre-purchase survey recommended that the shaft log cooling/sealing lines have cross connect capability. I know why that is a good idea but do not like adding more fittings, clamps (failure points) to any critical system. I guess the least intrusive way is to simply add a marine bronze "T" into each line and connect the two with the proper hose. Even that will add 6 new risks (joints with hose clamps) to a now simple system.

I am starting to think that a temporary hose and fitting (not installed until needed) is the right answer. Maybe a temporary fitting and hose arrangment that uses the washdown pump to supply water to the "dead" shaft" for the ride home? Of course that would mean taking the existing hose off the seal and hooking up this rig while at sea.

Maybe the real answer is to do nothing where you consider the seal burning up less of a risk than adding failure points to prevent it.

Any ideas?

[backman]

There was a long thread on boatdiesel about this

and one conclusion I took away was that your not going to burn up a freewheeling shaft seal in a couple hours of waterless 6 knot operation.

If you lose an engine your going to be reduced to 6 knots and will not put enough heat on that seal to cook it.

My marina wanted to do the cross connect and I too agreed less hoses and fittings is a good thing!

[PurpleCedarPlug]

Patriot,

There's a thread on here about a Month old that goes into detail on this issue.

Several of us have had this senerio, including myself. We came back in 25 nm on one engine and had no issue with the shaft on the engine that was not running.

I can't remember the name of the thread, but I would do a search and you'll probably find it.

My personal conclusion is I'm going to leave things as they are.

[BLUE MOON]

Hi to all,
I looked into this issue and was concerned about the cross-over back feeding into the stopped engine. So I installed flow sensors into the coolling lines and carry the parts to do a cross feed tube in an emergancy.

I did a lot of testing to determine the sensors to use and the following is information about the ones I chose.:

I purchased the chosen switches from a company called Harwill (http://www.harwil.com/Q12N-Install.shtml). They were great, they essentially custom design the switch to fit the application. The part number for the switches I am using is “Q-12N-C2/3/4NPT/3SM/NC/1FT/3/4TTT/3/8ORIFICE”, which details the configuration. Even being custom built the price was $ 60.50 each.

I ran these sensors all last season and they worked great.

Steve
"BLUE-MOON"
CC 32

[Patriot]

Blue Moon-

That was a pretty big project and looks very nice. I have pretty much decided to do nothing as I really don't like the idea of making a simple system complicated. Adding numerous joints and the hose clamps associated just doesn't sit well with me on any system open to the ocean. IF I have a problem, I will live with a 6kt ride home. Not sure if anyone has ever tested the theory but I wonder how fast a CC28 will go on one engine anyway? I will take a guess that you are not going to run on plane and after 6 kts you are just pushing water with this hull anyway until you reach planing speed. I question what there is to be gained unless you could either (a) run fast on one engine or (b) the shaft seal will eat itself at 6 kts without cooling water.

If someone could tell me that a CC28 will plane off and cruise on one engine, I would reconsider by current thinking.

[BLUE MOON]

Patriot
It is my understanding that the seals do not need cooling water below 8-10 knots. I was more concerned about having a blockage in the small feed line while at cruise speed. That is why I chose to install the sensors to monitor the cooling flow.

Steve
"BLUE-MOON"
CC32

[backman]

I have tested on one engine

6 knots baby; that's all you get.

You can't plane with either a KAMD 42 or a D4-260 and even if I could I would not do it for fear over overloading the engine. That's a sure recipe in my mind for a future problem.

When i broke a shaft last year I came home 8.82 nmiles at 6'ish knots running at trolling speed one one engine and keeping throttle at 1350 RPM to avoid engaging the turbo.

[TwinFin]

BlueMoon

Do you happen to know what sort (magnitude) of flow rates you are monitoring? I've wondered what the shaft seal cooling water flow rates on my 28 are. I've thought about installing temp sensors on the shaft seals but flow sensors are also interesting.

Also did your 32 come with raw water flow sensors and exhaust temp sensors or did you add those yourself?

[BLUE MOON]

TwinFin,
The only flow rate that I could get any info on was that at idle you should have 1 gallon per min. I installed the other flow and overheat sensors.

Steve
"BLUE-MOON" CC 32

[TwinFin]

Thanks

Steve, I like that set-up.

Steve

[BLUE MOON]

Twin Fin,
If you send me a private message with your E-mail address, I can send you a word.doc detailing all of the add-ons I installed. It includes purchasing links.

Steve
"BLUE-MOON"
CC32

[CHUCKABEAR]

running on one engine!!!

talked with wade yesterday @ the factory, he told me directly not to worry about running one motor with the other down,for whatever reason, the shaft logs will not burn up,melt, or become damaged,other members have experienced this also..read other threads... but like backman said i would not try to run the other engine hard,, there could be a difference between 6 knots and 8...