US navy finds wreck of missing yacht Cheeki Rafiki

[erice 732]

yes, monel rivets i've drilled out of alloy masts have always looked weathered silver with a tiny hint of greenish brown

 

 

 

5 years crevice corrosion on a below water rudder bolt

 

 

http://www.alberg30.org/maintenance/Ste ... Corrosion/

[wheels 543]

There are (I think) 5 different Grades of Monel. They are made mostly of about 2/3rds Nickel and 1/3rd Copper(ruffly, the amounts Vary with Grades. Then depending on the Grades, they have small amounts of Iron and Magnesium. One Grade is ultra hard and has additional amounts of Aluminium and Titanium. Monel can withstand tremendous heat without deforming and oxidizing.

It is highly prone to Galvanic corrosion if placed against any other metal though. It must always be isolated if in contact with Iron or SST. So if you use it as Keel Bolts, ensure you use Monel washers and Nuts as well.

There is famous story of a 200ft Yacht launched in the US in the early 1900's that had the outer Hull built completely out of Monel. They expected the Hull to be extremely strong and corrosion proof. But the Hull disintegrated in just a mere 6 weeks because the inner Frame Work was Steel and Galvanic Corrosion was unbelievable. They had to send the 6 week old Vessel to Scrap.

[sow1ld 2]

I think marine Monel bolts are 400n grade and they do tend to have a copperish colour over time. Here's a pic of the monel bolts and phosphor bronze nuts on my boat all cleaned up. When I take the keel off I will make up new one piece washers for the double bolts as it is much stronger than individual washes. Just to be extra sure I'll get more nuts so that I can double them up.

[Guest]

just for wineglass, canters are not immune to metal fatigue in some way or another

[sow1ld 2]

Crevic corrosion?

[Guest]

more anodic in this case, which I guess is still crevic of sorts.

 

four different metals and carbon to boot ...........

[MarkMT 68]

There is famous story of a 200ft Yacht launched in the US in the early 1900's...

http://query.nytimes.com/mem/archive-free/pdf?res=9802EEDD1138E633A25751C1A96E9C946496D6CF

[wheels 543]

Crevic corrosion?

It's Galvanic. It has been reacting between the two metals, (or Carbon). I am also wondering if that Bearing carrier piece has been welded on the the greater piece of metal. It is highly possible for the Weld area to be dissimilar enough to cause Corrosion also.

[BNG 44]

Black Fun had galv bolts (3 x M20 transverse/horizontal bolts/nuts holding keel fin into socket)

 

After 10 years I hit them with some WD40, overtightened them weekly for 3 weeks to crack any adhesion to the hull then backed them off and tapped them out and they were mint. Had been quite wet from time to time too. Galv on galv tho - the internals of the keel fin were galv steam pipe, macrocarpa, carbon foil over.

 

Even after cutting around the socket the keel still wouldn't fall off even when hung from hiab and big, big hammer whacks. So it was sabre-saw time... and off she came.

 

Guess who the grey haired guy is...

[John B 106]

I wonder.

 

I see there's an outstandingly refurbished Whiting half tonner ? sitting on cradle bunks beside her keel at okahu bay ATM.

[sailinghigh 0]

Thanks all you guys - valuable information and very educational.

 

 

The moral on the story re Cheeki Rafiki the Young Skipper obviously did not know all this info and the passed history re the design.

 

The bilge pumps obviously where insufficient like most sailing, and motor vessels. My experience with vessels I have crewed on, visited and during discussions I have determined most vessels seem to have bilge pumps with less than a total capacity 1000 gph,

with a lot having only 500 gph & 750 gph. This is mainly due mainly due to expense and thinking a major leak will not happen to them. I remember a American yacht that lost the propeller drive shaft 3/4 inch and the bilge pump and the NZ regs hand bilge pump, plus bucket bailing could not stem the flow. They almost abandoned ship, fearing water sudden movement instability, should a wave or the vessel tilt side ways causing a instant capsize, as the water level was half way to their knees before successfully tying and tapping a heavy plastic bag around the shaft.

 

Ocean going now I always only sail on vessels with at least 9000 gph ideally prefer minimum 16,000 gph which is 4x 4000 gph auto float switch bilge pumps with a activating light at the helm or at the engine instrument panel for each individual pump.

 

The Cheeki Rafiki where communicating for a considerable period with the charter company ,plus notified them they where heading to the Azores and could not determine where the water was coming from. A crew member also posted a post on a blog on the internet. Then suddenly they lost contact. Obviously insufficient bilge pumps to completely pump the sole dry to see where the entry point was.

 

They should have, at the point when they could not determine entry, abandon ship.

 

The skipper 21 was being paid for the delivery the rest where volunteer crew members, presumably from crew available forums as a guess.

 

Was this a privately owned vessel or a charter vessel?

Any body know?

 

Also they activated their 2 PLBs individually 24 hrs approx. apart as the batteries where drained.

 

Be interested to know if they had a EPIRB on board as some yacht clubs and country safety regs allow 2 PLS instead, avoiding the need for a EPIRB. Charter Company- who knows.

 

The coast guard stated they could not pin point their position as they where using non homing PLBs only a Lat - Long satellite co ordinates as opposed to a EPIRB with position finding homing 121 - frequency. Also the plbs are not designed to float with aerials pointing skyward. However the signals where received and they stated they where not EPIRB signals.

[Clipper 343]

They should have, at the point when they could not determine entry, abandon ship.

 

 

Umm... Big call.....

[Guest]

Yep - I always thought it was best to step up into a liferaft.....

[Guest]

What I find interesting is that no one seems to have considered that the crew may well be in the yachts tender. Any sailboat going or coming from the Caribbean would in all probability have had a good workable inflatable tender on board. Knowing the yacht was in serious trouble, they could have got the tender inflated and in a ready to go position. Certainly in all my offshore cruising, we always considered the inflatable as part of our abandon ship plan. Two floating platforms are better than one.

 

It is quite possible that they were somewhat prepared, when suddenly the keel dropped off. There is the possibility they managed to launch the inflatable and are still floating out there. Unless of information dictates there was no dinghy on board?

[sailinghigh 0]

What I find interesting is that no one seems to have considered that the crew may well be in the yachts tender. Any sailboat going or coming from the Caribbean would in all probability have had a good workable inflatable tender on board. Knowing the yacht was in serious trouble, they could have got the tender inflated and in a ready to go position. Certainly in all my offshore cruising, we always considered the inflatable as part of our abandon ship plan. Two floating platforms are better than one.

 

It is quite possible that they were somewhat prepared, when suddenly the keel dropped off. There is the possibility they managed to launch the inflatable and are still floating out there. Unless of information dictates there was no dinghy on board?

 

Possible I agree but 16ft seas and the wind strength at that reported time 50 mph blowing.

 

Perhaps trapped with the air pocket.

 

Just a coincidence the USA waited 48 hrs approx. the time before they mounted the search. The time the PLBS where flat. The next on kin complained why did they wait so long. They uscg had the last lat long co ordinances but claim could not hom.

 

Pure speculation on my part I must admit.

[Guest]

What I find interesting is that no one seems to have considered that the crew may well be in the yachts tender. Any sailboat going or coming from the Caribbean would in all probability have had a good workable inflatable tender on board. Knowing the yacht was in serious trouble, they could have got the tender inflated and in a ready to go position. Certainly in all my offshore cruising, we always considered the inflatable as part of our abandon ship plan. Two floating platforms are better than one.

 

It is quite possible that they were somewhat prepared, when suddenly the keel dropped off. There is the possibility they managed to launch the inflatable and are still floating out there. Unless of information dictates there was no dinghy on board?

 

Good thought but When keels fall off, the boat floats. So why abandon a large floating boat for a rubber ducky.

 

They may have been tethered to it and broke away. But I would take my chances in the yacht than a rubber raft.

[Island Time 1,235]

Interesting media report from Manslaughter trial of mamagement company and it's director;

 

http://www.dailymail.co.uk/news/article-4584880/British-sailors-died-told-shortcut.html

 

Seems to confirm all our suspicions - prior damage - poor maintenance.