NormanS
Well-Known Member
Blimey, that's a sweeping statement.
Thinking of all the civil engineering constructed using concrete, what sort of time scale are you looking at?
mooring block?
- Thread starter Niander
- Start date
Blimey, that's a sweeping statement.
Thinking of all the civil engineering constructed using concrete, what sort of time scale are you looking at?
Jcorstorphine
Well-Known Member
Any more...?
I noticed that the eye of the shackle is eroded as well, might be an electrolytic action here. Might be the mousing wire eating away the steel of the shackle. One NO NO is to use copper wire to secure the shackle.
Lady Campanula
N/A
I have no idea what was fitted when the above was new. The reality is that no - repeat NO - mooring assemblies remain new for more than a few hours. As no-one has produced any means whatever of predicting wear/corrosion rates, the only reliable technique is to fit really good kit, inspect it frequently, replace at the first signs of trouble - and record what you measure so you can show your insurers....
Do remember that, if your boat goes walkabout and smashes into others - or splits its diesel tanks pounding against the harbour wall - there may be a far larger bill to meet than just the cost of hauling your wreck out of the water.
And, if you neglect to have evidence of maintenance to put in front of your insurers when they ask, you may well have to meet those bills on your own...
Niander
Well-Known Member
Box is 4 foot lg
what size yacht..25 to 30 foot
One NO NO is to use copper wire to secure the shackle.
plastic cable ties seem to be the best for this!
Not sure how long the riser chain needs to be?
also size of chain?
what size yacht..25 to 30 foot
One NO NO is to use copper wire to secure the shackle.
plastic cable ties seem to be the best for this!
Not sure how long the riser chain needs to be?
also size of chain?
dylanwinter
Well-Known Member
the professionals in action
plastic ties being used
http://www.youtube.com/watch?v=bN1Ay5jXnhY
Dylan
plastic ties being used
http://www.youtube.com/watch?v=bN1Ay5jXnhY
Dylan
Heckler
Well-Known Member
Given that we can now buy Dyneema "shackles" why cant we use this material instead of steel?I have no idea what was fitted when the above was new. The reality is that no - repeat NO - mooring assemblies remain new for more than a few hours. As no-one has produced any means whatever of predicting wear/corrosion rates, the only reliable technique is to fit really good kit, inspect it frequently, replace at the first signs of trouble - and record what you measure so you can show your insurers....
Do remember that, if your boat goes walkabout and smashes into others - or splits its diesel tanks pounding against the harbour wall - there may be a far larger bill to meet than just the cost of hauling your wreck out of the water.
And, if you neglect to have evidence of maintenance to put in front of your insurers when they ask, you may well have to meet those bills on your own...
Stu
theoldplucker
Well-Known Member
We do like 'un to last a long time down 'ere ! Also we've got plenty of granite. Concrete, especially with lumps of steel in, can break up. 'Concrete cancer' occurs in air, must also be a risk under water.
Another point - never use stainless steel swivels or shackles mixed with steel - causes fast corrosion. Have known moorings break because of this.
I use two shackles at each join. Use a smaller one through links so that if this breaks, the larger one is a security. Mouse shackles with a cable tie and seizing wire. Cable ties can degrade in UV light.
Lady Campanula
N/A
I think that's a question best put to your insurers. If they indicate their satisfaction in writing, then 'bob's your uncle'....
Heckler
Well-Known Member
In the nicest possible way, we dont have to tell or get permission to use steel. So going back to the original question, is there a reason why we cant use Dyneema?I think that's a question best put to your insurers. If they indicate their satisfaction in writing, then 'bob's your uncle'....
Stu
Jcorstorphine
Well-Known Member
I would be really really really worried about the fibres being chaffed on the seabed with the abrasive action of sand. I don’t trust steel shackles but would not sleep at night with a "bit of string" holding my boat.
sarabande
Well-Known Member
it seems that Dyneema can be used successfully underwater, with a "deltaflex" cover:-
http://www.pressreleasefinder.com/rss.asp?id=7893
and here's the Deltaflex details:-
http://www.deltaflex.com/
which makes it look like a very tough rubber cover.
Mountaineers use Dyneema a lot, but how it copes with running over rock (jimi ???).
It is also in use for fishing trawls, so there must be some considerable operational advantages to using it instead of steel rope or chain.
http://www.worldfishing.net/news101/van-beelen-continues-success
http://www.pressreleasefinder.com/rss.asp?id=7893
and here's the Deltaflex details:-
http://www.deltaflex.com/
which makes it look like a very tough rubber cover.
Mountaineers use Dyneema a lot, but how it copes with running over rock (jimi ???).
It is also in use for fishing trawls, so there must be some considerable operational advantages to using it instead of steel rope or chain.
http://www.worldfishing.net/news101/van-beelen-continues-success
Heckler
Well-Known Member
At the back of my mind is something I saw about replacing stainless standing rigging with Dyneema. If it is good enough to do that? Plus all the examples you have found, perhaps peeps should be considering it.
Stu
Bosun Higgs
N/A
I always thought you were supposed to cast a concave shape in the bottom of the concrete inside a tractor tyre so as to have suction in the sea bed mud.
