I trashed five seacocks at sea!

Babylon

Well-known member
Joined
7 Jan 2008
Messages
4,265
Location
Solent
Visit site
Dear reader, this thread involves a huge amount of maximum stupidity, and I'm lucky not to have lost my ship or any lives.

As regulars on this forum know, I re-engined my boat this winter with a new Beta 25, doing pretty much all the installation work myself, the engineer then checked everything before running up the engine and signing off the warranty. I then connected the seacock and hull-anode bonding wire to the engine block.

Two weeks later, returning from the first weekend cruise of the season, I found I had a dead engine starting-battery (although the day was saved by jump-starting from the domestic bank). As the battery was five years old, I reckoned it was finished and bought a new one at vast expense.

Last weekend, at anchor in Poole, we were about to go to bed when I chanced to check the engine battery voltage and found it dead! As we were on a bit of a lee-shore, I jump-started the engine and moved for peace of mind to an empty mooring-buoy for the night.

On returning to the Solent, we decided to spend the night in Lymington rather than head home to the Hamble, and the following day I had a local electrician on board to check what was going on. What in fact was going on was that I'd secured the seacock bonding wire to the starter-motor positive!! The meter was reading 16amps to the bonding circuit whenever the engine battery was on, whether we were running the engine or not. Bloody idiot! Complete bloody fool! Bloody hell!

We immediately shifted ourselves to the harbour wall, where at LW neaps we touched but ony half dried-out and at 1.00am I was in the water in a drysuit inspecting the damage (and avoiding floaters). We spent the rest of the night on alternate seacock-watches before a 6.30am call to the engineer I'd contacted the evening before who rocked up promptly and ordered all parts before the delivery truck left Aquafax at 8.00am. He also got the Yacht Haven to agree to an emergency lift-out first thing.

The damage:
* New 3/4" engine intake seacock - lost entire outer flange, half of threaded area and only held on by the brand new Sikaflex under the internal flange! (full replacement)
* Old 3/4" galley-sink outlet seacock - badly corroded and weeping (full replacement).
* Old 1/2" raw-water intake (to galley) - broke off in my hand (full replacement).
* Both old Blakes heads seacocks - outer flanges and bolts badly corroded (only replaced these parts)
* New MG Duff large hull anode - lost 1/4" all round (but still plenty left).
* New Featherstream prop anode - lost 1/8" all round (still plenty left for the season).

The only two seacocks that didn't seem effected were the heads sink outlet which is on the waterline (it was cleaner than before but hadn't lost any structural material), and the cockpit drain seacock, which isn't bonded at all (this might be to do with the fact that it also contains the heat-exchanger for the fridge?).

We worked non-stop during the day removing and replacing all damaged seacocks etc and fitting new, before being lifted-in last thing before the crew left for the long weekend.

Of everying stupid thing I've ever done, this - but for the grace of the ineffable - was the most cretinous. At best I'd have sunk my boat on her mooring. At worst I'd have put the lives of my crew and others at risk.

I take full responsibility for my idiocy.

Babylon

PS For those interested in who the two fine Lymington professionals are, their details for future use are:
Electrician: Andy Newport 07521 390052.
Engineer: Clive Rochfort 07753 558610.
 
Last edited:

doug748

Well-known member
Joined
1 Oct 2002
Messages
12,921
Location
UK. South West.
Visit site
Thanks for sharing that one Babylon.

I guess you were looking for a place to bond to and a handy post and nut hove into view. Easy to do if you are a bit pressed and don't have the leisure to think things through.

I nearly caused a fire once through not grasping the hidden danger of short circuit in a windcharger system directly connected to a battery.
 

Tranona

Well-known member
Joined
10 Nov 2007
Messages
41,194
Visit site
Lucky escape! Suggest you unbond all your seacocks from the anode. It really is unnecessary on most GRP boats as the seacocks are not electrically connected to anything. You may also find you don't need an anode at all as the Featherstream anode will look after the prop, but you might want to bond the external hull anode to the shaft just in case.
 

Seajet

...
Joined
23 Sep 2010
Messages
29,177
Location
West Sussex / Hants
Visit site
Babylon,

you're to be applauded for passing on the warning.

Don't be so hard on yourself, you're not the first and won't be the last to do this.

Also, once the snag was realised you didn't pussyfoot around, but went straight for a thorough, expensive repair.

I'd much rather sail with someone who realises something is wrong and investigates - a depressingly large percentage of people would have put their heads in the sand - then admits a mistake and sorts it properly, than someone who tries to wing it, and /or blame someone else !
 

Babylon

Well-known member
Joined
7 Jan 2008
Messages
4,265
Location
Solent
Visit site
Lucky escape! Suggest you unbond all your seacocks from the anode. It really is unnecessary on most GRP boats as the seacocks are not electrically connected to anything. You may also find you don't need an anode at all as the Featherstream anode will look after the prop, but you might want to bond the external hull anode to the shaft just in case.

Thanks for this. But what about stray currents in marinas and the suchlike? Note that my big hull-anode and the little rudder-skeg anode both 'suffer' from some erosion even though I'm on a mid-river mooring. Surely its worth keeping everthing bonded as is? Can't harm, can it?

Babylon

PS I've just had a horrible thought: what if some complete moron in a marina berth next to me had his own seacocks bonded to the engine positive?
 
Last edited:

NorthUp

Active member
Joined
1 Sep 2008
Messages
1,490
Visit site
I hate to add to your troubles, but I suspect your Beta heat exchanger core will have suffered a similar fate to the seacocks, and probably the Jabsco pump internals as well.
A quick check would be to inspect the inside face of the Jabsco (Johnson?) for erosion.

Edit- and there is a copper pipe from the pump to the heat exchanger to check as well!
 
Last edited:

Babylon

Well-known member
Joined
7 Jan 2008
Messages
4,265
Location
Solent
Visit site
I hate to add to your troubles, but I suspect your Beta heat exchanger core will have suffered a similar fate to the seacocks, and probably the Jabsco pump internals as well.
A quick check would be to inspect the inside face of the Jabsco (Johnson?) for erosion.

Edit- and there is a copper pipe from the pump to the heat exchanger to check as well!

I don't understand this (but there again I've demonstrated already how ignorant I've been!). How would the heat-exchanger, Jabsco/Johnson pump, copper-pipe have been effected? What part of the circuit would they have been in?
 

john_morris_uk

Well-known member
Joined
3 Jul 2002
Messages
27,386
Location
At sea somewhere.
yachtserendipity.wordpress.com
Surely its worth keeping everthing bonded as is? Can't harm, can it?

The short answer is yes it can

So long as the sea cocks are of good quality bronze or DZR and they AREN'T connected to anything else electrically, they will be fine. In fact it was the way they were bonded caused the problems! (Sorry to rub salt into the wounds and all that.)

Only bond things to a sacrificial anode that NEED to be bonded, ie because they are already connected to other less noble metals electrically and are both immersed or in direct contact with the sea-water.
 

Babylon

Well-known member
Joined
7 Jan 2008
Messages
4,265
Location
Solent
Visit site
Good question!

as a general point, would insurance cover such an event ?

Mmmm, good question.

I telephoned my broker once day had broken and he was back from dropping the kids at school, and he informed me that MY insurance policy covers 'user negligence' - which means me! Had it been an engineer's fault, then the claim would have been through his insurance.

As it happens, the total cost (lift/scrub/block-off, relaunch, engineer and parts) comes to roughly £650, plus I suppose the £90 I already paid Barden for a new battery two weeks ago which now needs drop-testing to check it isn't permanently damaged. So if insurance didn't cover it, I'd not ony be a very chastened individual, I'd also be sick as the proverbial colourful bird.
 

NorthUp

Active member
Joined
1 Sep 2008
Messages
1,490
Visit site
I don't understand this (but there again I've demonstrated already how ignorant I've been!). How would the heat-exchanger, Jabsco/Johnson pump, copper-pipe have been effected? What part of the circuit would they have been in?

Do you have another wire connecting the engine block to the anode, and the seacocks? If so then any metal parts thus connected and in contact with sea water (internally) will form part of the circuit which zapped your seacocks.
If the engine block is not connected then you should be OK- was this the wire which ended up on the starter positive in error?
 

Babylon

Well-known member
Joined
7 Jan 2008
Messages
4,265
Location
Solent
Visit site
The short answer is yes it can

So long as the sea cocks are of good quality bronze or DZR and they AREN'T connected to anything else electrically, they will be fine. In fact it was the way they were bonded caused the problems! (Sorry to rub salt into the wounds and all that.)

Only bond things to a sacrificial anode that NEED to be bonded, ie because they are already connected to other less noble metals electrically and are both immersed or in direct contact with the sea-water.

So what you're saying is this: disconnect all seacocks from the circuit (yes they are all bronze or DZR), but keep the hull anode bonded to the engine negative to protect the propshaft etc?

Re rubbing salt into the wound (I'm so ashamed of my error that I'm even prepared to supply the salt!), if I hadn't had the seacocks bonded when I made my original mistake, then the only damage I'd have suffered, in addition to a flattened battery, would have been eroded zink anodes (on hull, on prop, on rudder skeg)?
 

john_morris_uk

Well-known member
Joined
3 Jul 2002
Messages
27,386
Location
At sea somewhere.
yachtserendipity.wordpress.com
So what you're saying is this: disconnect all seacocks from the circuit (yes they are all bronze or DZR), but keep the hull anode bonded to the engine negative to protect the propshaft etc?
Yes - got it in one. Just make sure that the hull anode is connected to the propeller and any other metal you have got underwater...

Don't know about the latter part of your question as I don't know what was connected to what exactly - except the bit you mentioned etc.
 

Babylon

Well-known member
Joined
7 Jan 2008
Messages
4,265
Location
Solent
Visit site
Do you have another wire connecting the engine block to the anode, and the seacocks? If so then any metal parts thus connected and in contact with sea water (internally) will form part of the circuit which zapped your seacocks.
If the engine block is not connected then you should be OK- was this the wire which ended up on the starter positive in error?

I'm still thinking through the enormity of this...

1. The engine is earthed (negative).
2. The anode and seacocks were bonded to the starter (positive).
3. When 16amps (positive) were being pumped to them, they reacted with the seawater and eroded.
4. I assumed that they eroded because the seawater has its own earth (negative) elsewhere.
5. But did they also erode because the seawater was in contact with raw-water side of the engine cooling system (negative)?
6. If this is the case, would the parts on the engine (negative) side of the circuit also have eroded?
 

Tranona

Well-known member
Joined
10 Nov 2007
Messages
41,194
Visit site
From what you say, it is unlikely that the hull anode was doing anything for the stern gear if you have a flexible coupling as that isolates the engine from the shaft and prop. The most common arrangement is some sort of anode on the prop, particularly if it is mixed metals like yours and a hull anode bonded to the shaft either through the engine and with a bridge across the coupling or brushes on the shaft. I have had my boat in a marina year round since 1995, half of that time with a JF prop similar to yours and a hull anode bonded to the engine. In that time I have only replaced the anodes once - and the prop one because there was a new type available. Two out of my 4 seacocks are the original 1963 and one (the engine intake) has just been replaced for the engine upgrade and was in perfect condition after 18 years.

You will, however have to keep an eye on the engine anode as the heat exchanger is mixed metals so the anode often works hard.

Problems in marinas are usually caused by being plugged into shorepower and can be minimised by fitting a galvanic isolator. Boats with saildrives can also have problems simply because of the mix of metals and limited size of anodes on some models.
 

Ubergeekian

New member
Joined
23 Jun 2004
Messages
9,904
Location
Me: Castle Douglas, SW Scotland. Boats: Kirkcudbri
www.drmegaphone.com
I'm still thinking through the enormity of this...

1. The engine is earthed (negative).
2. The anode and seacocks were bonded to the starter (positive).
3. When 16amps (positive) were being pumped to them, they reacted with the seawater and eroded.
4. I assumed that they eroded because the seawater has its own earth (negative) elsewhere.
5. But did they also erode because the seawater was in contact with raw-water side of the engine cooling system (negative)?
6. If this is the case, would the parts on the engine (negative) side of the circuit also have eroded?

VicS is yer man for this, but my guess is that your propeller would have been fizzing away happily in a cloud of, erm, hydrogen-I-think bubbles.
 

VicS

Well-known member
Joined
13 Jul 2002
Messages
48,311
Visit site
The point is made above that that connecting bronze or DZR seacocks to anodes should be unnecessary.

Not only is it unnecessary but one of the recommendations made by the MAIB in their investigation into the near loss of the fishing vessel Random Harvest some years ago was that the the seacocks should NOT be connected to the anode system.

See http://www.maib.gov.uk/cms_resources.cfm?file=/random%20harvest.pdf
 
Last edited:

Babylon

Well-known member
Joined
7 Jan 2008
Messages
4,265
Location
Solent
Visit site
From what you say, it is unlikely that the hull anode was doing anything for the stern gear if you have a flexible coupling as that isolates the engine from the shaft and prop. The most common arrangement is some sort of anode on the prop, particularly if it is mixed metals like yours and a hull anode bonded to the shaft either through the engine and with a bridge across the coupling or brushes on the shaft...

You will, however have to keep an eye on the engine anode as the heat exchanger is mixed metals so the anode often works hard.

Yes, there's a bridge across the coupling, so that connects the hull anode to the stern gear.

Will check the engine anode, but if its gone competely then will start worrying about the state of the metals from the raw-water pump on through...
 
Top