BartW Sink a boat got me thinking

Petrolia

Petrolia

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Reading BartW thread on sinking boat. Talk about filters being downstream of pumps and the fact it shouldn't be like this.

If so my boat is plumbed wrong. Pumps suck from sea and deliver straight into filters. AND I've also had the problem mentioned of water into engine bay if filter covers not on tight.

So why would a relatively new boat be plumbed 'wrong' like this. Is this Volvo or Nimbus error ?
 
I'm not sure wrong is the best way to put it...

It depends on the system design, there is probably some logic as to the detail.

The old OMC raw water pump was mounted in the upper part of the drive and the water was then pumped through the transom shield and into the engine. In that case the water is screened through a mesh screen at the intake.

We now have an additional raw water strainer in the engine bay.
 
carlton said:
You're worrying unneccessarily. IMHO it's far more more important to ensure all your hoses are connected properly before starting up the engine. :rolleyes:
Click to expand...


Connected fine. Now wheres that clip? Anyway the supervisor knows where the bilge pump switch is!
 
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So why would a relatively new boat be plumbed 'wrong' like this.

It's not plumbed wrong, there are two thoughts on the matter..........

1. If the filter is before the pump it will stop any debris damaging the pump if you are unlucky enough to pick any up!

2. If the filter is after the pump it will catch any damaged parts of the pump before they get to the coolers.

It's not unusual to see Trawler yachts with two filters one before and one after the pump, this is so that any of the pump vanes that may detach don't end up in the coolers blocking them and causing overheat problems. Many times people find that vanes are missing from their pumps and then change the impeller, then dont go looking for where the bits ended up only to find that when they need to use full power the engine over heats.

Like everything in life we all have opinions, me.....well mine is before the pump and I change the impeller every year! if I was to find a vane missing I would be looking for it before venturing out to sea, but that's just me!

Tom
 
You're right there is an upside to having the filter after the pump. In fact I had an impellor shred once and guess where I found the pieces. Yep, in the filter.

Should have thought of that myself. Dummy.
Happy now.
 
As I say the OMC drive has a mesh screen at the intake port in the leg. The volvo drives may (i suspect likely) too.
 
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