Boating at sea

[blackrose]

 

While having the greatest admiration for all the work that the RNLI do, I'm afraid that this also is a classic case of towing much too fast in adverse weather conditions with a tow line that is too short, which is often the cause of a parted towline, or worse, the foundering of a casualty.

 

Howard

 

Yeah, but it made a great Youtube video!

[Joe Bourke]

 

Plays havoc with fresh water anodes - they will need replacing after a week on salty stuff.

[Murflynn]

 

While having the greatest admiration for all the work that the RNLI do, I'm afraid that this also is a classic case of towing much too fast in adverse weather conditions with a tow line that is too short, which is often the cause of a parted towline, or worse, the foundering of a casualty.

 

Howard

disagree.

if you watch carefully, in the big swells the barge is just reacting as if it was on a long anchor cable - with no forward movement over the ground.

in the calmer bits the speed of the boat relative to the water is easier to determine - maybe 1 to 2 knots max.

[howardang]

disagree.

if you watch carefully, in the big swells the barge is just reacting as if it was on a long anchor cable - with no forward movement over the ground.

in the calmer bits the speed of the boat relative to the water is easier to determine - maybe 1 to 2 knots max.

Sorry, but we'll just have to disagree. I have seen that clip a number of times and I haven't changed my opinion.

 

Howard

[blackrose]

I don't know enough about towing boats in heavy swells to either agree or disagree. But I can't help thinking that the RNLI know what they're doing.

 

But I suppose the bottom line is, did they get the boat back in one piece or did it sink?

 

It wasn't quite that calm when we went.

 

Very short bit of video here:

 

https://www.youtube.com/watch?feature=player_embedded&v=D7m3rDapx1o

 

(It had been a fair bit rougher but I was holding on too tightly to use the camera)

 

That's not too bad Alan. My boat's been through a rougher conditions that than on the tidal Thames.

[Joe Bourke]

 

 

Plays havoc with fresh water anodes - they will need replacing after a week on salty stuff.

Really?

[steamcompound]

http://www.boatingmag.com/how-to/choosing-right-sacrificial-anode

 

Just an application of the electrochemical series.

[Alan de Enfield]

Really?

 

Yes - Really !!

 

Inland waterways boats generally use magnesium anodes whilst sea water based boats uses Zinc anodes.

 

In salt water Magnesium anodes erode approximately 3x faster than Zincs due to the ease in which it gives up its electrons, and the increased conductivity of seawater.

 

And - to precis Boating magazine "..... In fact, if you take a freshwater boat protected by magnesium anodes to the coast and put it on a mooring for a week, you’ll have a catastrophe on your hands...."

 

Edit ; Steamy posted whilst I was typing - same information

Edited February 27, 2016 by Alan de Enfield

[Murflynn]

 

 

 

 

 

And - to precis Boating magazine "..... In fact, if you take a freshwater boat protected by magnesium anodes to the coast and put it on a mooring for a week, you’ll have a catastrophe on your hands...."

 

 

that's one hell of an exaggeration:

 

http://www.boatingmag.com/how-to/choosing-right-sacrificial-anode

[Joe Bourke]

What would the catastrophe be?

[steamcompound]

Bronze prop + scratched steel hull + sacrificial anodes gives loss of anode and protected steel hull.

 

Bronze Prop + scratched steel hull + eroded away anode gives heavy local corrosion in scratched areas.

 

The vessel in the accompanying images is kept in fresh water but has no anodes. The "barnacles" on the mild steel shaft, skeg and rudder are rust, the steelwork being deeply pitted in parts. The steel is chemically more active than the bronze. Sea and brackish water is much more aggressive than fresh because of the salt and other dissolved minerals.

Edited February 27, 2016 by steamcompound

[Joe Bourke]

Thanks for that, but I was mainly interested in the bit about magnesium anodes in salt water for a week and catastrophic consequences. We moor in Goole, and go onto salty water, quite regularly, might consider aluminium anodes when we dry dock in May. To be honest though our present anodes seem to be holding up well.

[Pennie]

Oh I forgot I even posted this. Should not drink and internet lol

 

Will have a look through all the posts when Ben is around to learn about it too. Thanks for all the comments :-)

[Loafer]

Oh I forgot I even posted this. Should not drink and internet lol

 

Will have a look through all the posts when Ben is around to learn about it too. Thanks for all the comments :-)

 

C'mon Pennie, ease up on the pop for a bit!