seawater cooling circuit monitoring Q

[MapisM]

Feels like you have not studied Chemistry.

Absolutely correct.
But having dealt with several high profile Chemists (including a Distinguished Professor and a Lecturer), I'm glad I didn't, tbh.
That might be one of the reasons why I only understand reasonings as long as they don't defy common sense...
You previously said that the transom anode "needs seawater to create a circuit for the movement of the various protective subatomic particles", and that's what inspired my objection.

 

[Portofino]

Actually P bear with me .
You close your main seacock
Fresh water flush with the none OEM DIY kit .
Let’s have a think ?
There’s a copper strip connected to the transom anode from the engine.
That’s sat in a salty solution in fact v salty Med :
Your ball valve in the seacock is the barrier -Yes - closed to keep the salt out ?
So any protective sub atomic particles have now to pass through that ball valve - yes .
They will as there’s a huge now difference of electric potential- sea - ball - fresh connected via the transom anode .
So what’s that made of ? The actual valve bit that closes the cock , not the body or the skin fitting .
Hmmm indeed. Depending on the electrochemical difference between the external solution ( sea ) , the zinc ( basically connected to the engine) AND the barrier the ball = whoops if closed dezincification / corrosion of that out of sight .component .

Let everything that leaves your transom zinc find its way to what’s it trying to protect : don’t put barriers up

 

[MapisM]

Let everything that leaves your transom zinc find its way to what’s it trying to protect: don’t put barriers up

I'm not sure to understand your reasoning.
The ball inside the valve is made of s/steel (I suppose, simply because afaik all of them are), but also leaving aside the fresh water flush, the protection system is designed to work also with the seacock closed, surely?

 

[Portofino]

I'm not sure to understand your reasoning.
The ball inside the valve is made of s/steel (I suppose, simply because afaik all of them are), but also leaving aside the fresh water flush, the protection system is designed to work also with the seacock closed, surely?

Yes it’s more balanced sea -SS -sea on the other side
Both solutions either side more less identical so any electrochemical activity cancels . What’s added is netted off the ball as the subatomic particles move through or have an effect . So the ball does not deteriorate enough to be of any significance.
Maybe this helps ?

Remember musical chairs when you were a child ?
The chairs are the metals the kids the subatomic particles ( negative charged )

10 chairs in a classroom . 10 kids sat down
Next door down the corridor another 10 chairs another 10 kids in another class sat down .

One kid gets up in class 1 , now an empty chair then another = two empty chairs the row is “corroding “

Those kids walk out via the corridor from class 1 . Class ones chairs are hard and uncomfortable to sit on unstable they tipple over ( zinc )
Meanwhile in class 2 ( your coolers) the chairs are real comfy leather recliners etc . How ever nature calls and ad soon as a class 2 kids gets up to go to the loo a class 1 kid fills that place . So the empty depletion of kids in class 2 is basically none existent. The kids MOVE freely through both OPEN classroom doors via the corridor ( seawater ) .
It’s a big school ( the sea ) and returning kids from the loo to C 2 that can’t find a comfy seat just waltz off searching for another comfy seat through the open school . They don’t sit in C1 even though the door is open . Off they go into the big wide world of other folk , they dissolve into the “ sea “

So C1 depletes and C2 never depletes .
But only if the kids can move freely.
Closing the classroom door of C1 like closing your seacock and removing say oxygen in the corridor ( fresh water flush ) means there’s gonna be a eventual depletion of kids in C2 empty comfy chairs = corrosion.


With pencil anodes the zinc is actually touching the cooler casing embedded in it and hanging in the water . Theres no corridor here . So the 20 chairs are in two rows next to each other in the same classroom, the kids can climb about from one row to the next . Because it’s pretty obvious the comfy ones are better the kids jump on them without touching the ground,often two or more at once , this leaves many empty“ normal chairs “ in fact in some circumstances rapid depletion.
Problem is even these comfy chairs topple over with 3 kids flailing about . So the net is actually at any one time some empty comfy chairs as a few kids are on the floor = corrosion!
So flushing with water here - you basically are moving the two rows apart sufficient distance ( same room ) so to deter jumping across so the depletion rate of the anode decreases and most of if not all of the comfy chairs are occupied at any one time .Just like the C2 scenario.
Get the distance right between the two rows and fresh flush then it will be more stable as soon as a kid leaves a comfy chair a kid from a normal uncomfortable chair will move across in an orderly manor .
Some kids on the uncomfortable chairs might give up and walk out looking else where so that row will deplete eventually. Point is those kids can eyeball the other comfy row and are ready to pounce if a place is available. Thus no corrosion.
What happening in the corridor and rest of the school is irrelevant . Until the 10 uncomfortable kids are all gone - zinc depletion.

 

[vas]

PF you have a vivid imagination, I like the metaphors you use

as far as my boat is concerned, there are a couple of things to consider though

A. injection, ball valve and the diverter for the fresh water wash are all Trudesign, ie. grp, so no bronze/ss/whatever to mess with ions and kids moving about in chairs
B. managed to find 0-4bar decent quality (as in not from the depths of china) sensors made out of plastic! so bought 3, for 30quid each I might as well fit one to the geny as well...

So issue closed, except that on testing the oil cooler endcap, I realised that someone had fitted a mild steel M10X1 plug, which on removal and refit wouldn't tighten, tried to remove it and got back the hex and 1/3 of the bolt. Rest nicely tucked in the thread.
First opportunity I'm going to go through all the heat exchanger endcups and see what else have they messed and get some M10X1 plugs out of bronze made by my machinist to fit them all around!

cheers

V.

 

[vas]

closing the thread,

stbrd engine fitted and tested in the dock.
sensor fitted after the raw water pump on the endcap entering the charge air cooler - effectively the first one the seawater meets in the engine.

Idle speed: 0.4bar
1000rpm: 0.7bar
1800rpm: just over a bar

Will see if these values change with a warm engine and under stress, doubt much tbh.
So now if pressure is low, I know I've done something silly or strainer is blocked or impeller buggered
if pressure is high, generally pipework is blocked, time to clean the cores

cheers

V.