Help needed from someone with a powerful boat! (Spain)

E

EspenK

New Member
Joined
25 Jan 2011
Messages
20
Location
Southampton/ Oslo, Norway
Visit site
Posted this in another part of the forum aswell, but hope it's ok to spread the message a bit more.

Longshot, but.. I'm in kind of a pinch! I need to move my boat's mooring, consisting of tires filled with concrete, and my normal go-to guy is away at the moment. If anyone with a rib or similar would be interested in a short day's work (10 mins really, I need to have it moved about 20 metres) helping out a fellow boater and make a tiny bit of money doing so, pm me and we can agree on the details!

The boat is situated in South Eastern Spain, pm me for details:)
 
Espen, when you say that the mooring can be moved by a powerful RIB, I presume this means dragging the weights along the sea bed using the RIB?
If this is the case, then your mooring does not have much holding power, never mind that it weighs half a tonne (out of water - concrete weighs much less when immersed in water, as it is not very dense in comparison to sea water).

I would suggest that you add an anchor (any popular type will do) of a weight suitable for the size of vessel in tandem with the concrete weights to increase the holding power of the set up.
This would require a diver to go down and shackle on the anchor and chain to the blocks below - and if you have a diver involved, then it would also be worth asking if he has a lifting bag capable of lifting the concrete blocks.

Concrete typically has a density of 2,400 kg / cubic metre while seawater density is 1,025 kg / cu.m.
The 500 kg of concrete has a volume of approx 0.2 cu.m., and this volume of sea water weighs approx 200 kg, hence the effective weight of the 500 kg of concrete underwater would only be approx 300 kg (plus the weight of the mooring chain of course).

Lift the blocks off the bottom with a lifting bag, move them to the new location, add a 'proper' anchor for extra security, and rest happy.
 
The hazzle of moving permanent anchors has led to several design inventions.

Very popular, depending of sea bed, is this type:

01.1703-s.gif


, available in more sizes.

Once dropped it digs itself down and holds extremely well.
 
Thanks for input, it might be worth diving instead then.. Thing is, the mooring has been in position for almost a year now, and will only be used for another 2-3 months before the boat is permanently moved back to Norway, so I'm not too keen on investing a lot of time, effort and money at this point in time.
 
Does the actual mooring block(s) themselves HAVE to be moved about 20 metres (if yes, what is the reason?), or is it a case of the boat has to be moved?

This is probably a silly suggestion, but if it is ok for the boat (rather than the blocks) to be moved 20 metres, would it be possible to add some extra chain to the mooring, and perhaps also shackle on another length of chain and a standard anchor and then position this anchor to ensure that the mooring buoy stays in the new position?

It would then be relatively easy to retrieve the new anchor and chain in a few months time when you move back to high latitudes.
 
Well, in short; yes. That's what I've done now as a temporary fix. Problem is I'm not actually there to look after it, so there's no way for me to know whether the anchor's still there. Don't want to risk coming back in May to find the anchor line snapped and the keel broken off!
 
You must log in or register to reply here.

Share this page

Top