Buoy Management

[funrecdiver]

Hey LK,

Spoke with Robert of AD. Ideally with unlimited funds, a large ship with a crane and underwater communications gear to position a large concrete block, steel cable and an oil drum.

Under more practical and pragmatic economic conditions, 15 concrete poles dropped in the water one at a time, and repositioned by divers walking on the sea bed in the sand. Then, after repositioning the concrete poles, wrapping the steel cable under and around the pile of concrete logs.

He said that would be possible on a dive boat, since we have no dive boats (that we know of) with cranes on board that we know of and we don't have expensive underwater communications gear to position.

This "could" be a more permanent solution for each mooring line but theft by cutting the steel cable remains a possibility.

Assuming that around 100 meters of steel cable is required from the bottom; and then at least 15 concrete poles and a steel oil drum at the surface, we need to calculate the costs.

Since, it seems, that DCs have yet to do a similar community funded project like this with cheaper materials, do you think it can happen with a significantly more expensive community-funded project? With the risk of theft of an expensive steel cable, one could argue that a cheaper, easier dive community-funded project might have a higher probability of success that a more gold plated solution that also has risk of future theft.

 

[lord khram]

I dont think for one minute that cranes etc as you describe were either needed or used at the hard deep, what is your point?

Why 100 metres of cable? last time I dived at the kood the seabed was around 32m, and the Khram about 29m. Maybe you could visit the hard deep and have a look for yourself before making such elaborate assumptions.

To me it is more economical and practical, to provide a solution that is difficult to steal and unlikely to be a target of theft, rather than one that after a short spell of time will almost certainly be stolen as has happened countless times already. Just my thoughts.

Also I would like to add that I have heard discussions such as this numerous times around Pattaya over the years since the wrecks have been in place and generally nothing comes of it, maybe that is why now people seem to have very little interest in the subject.

Also I would add that in my mind the system has proved its self, the shot line at the Hard deep was installed some time ago and I believe it is still intact and functioning perfectly (certainly was the last time I dived there myself). lets see how long the next plastic buoy lasts on the Kood?

 

[funrecdiver]

I dont think for one minute that cranes etc as you describe were either needed or used at the hard deep, what is your point?

Cranes are how very heavy concrete blocks are normally loaded on boats and placed in the oceans. Concrete blocks are too heavy to be carried by mere humans onto boats from pier and from boats to dive sites. Your reply seemed defensive, which has me worried.

Why 100 metres of cable? last time I dived at the kood the seabed was around 32m, and the Khram about 29m. Maybe you could visit the hard deep and have a look for yourself before making such elaborate assumptions.

The general rule of thumb according to experts is 3 to 1 on mooring buoys (so I have been told). This means that if the bottom is at 30m, the length of the mooring line should be at least 90 meters. In addition, there should be additional length, for example, to wrap around concrete piles. I am not making any assumptions; however, your defensive tone in reply is not necessary. It seems obvious you don't know about mooring lines and how to calculate a length of one. However, I just spent a hour this evening talking to someone who has placed over 20 on local wrecks.

I am happy to continue the discussion with you, but if you could drop the "edge" in your reply, using terms like "elaborate assumptions" to describe a mooring line standard (as I have been informed) that you are not familiar with, that would be appreciated.

 

[funrecdiver]

Follow-up:

Just checked on this, and the 3 to 1 scope of a mooring line as we are talking about is actually very conservative. Marine standards for anchoring a boat is 5 to 7 times the depth to insure the boat is not destroyed during rough surface conditions.

If someone had a boat tied to a mooring buoy over the wreck and a very rough storm hit while divers were under water (certainly a high probability), having a dive boat on a mooring line that was 3 times the depth would be on the edge of "unsafe" as the standard Scope is 5 to 7 times depth for safely of the boat moored to the buoy over any site.

My own research confirms what Robert of Adventure Divers, who says he has put at least 20 mooring lines down on wrecks in the Pattaya area over the years (per Robert), is that a 3 to 1 ratio, length to depth, is the very minimum, for boat safety. A minimal amount of research on the net tends to confirm at least a 3 to 1 scope, for example:

Reference

Scope is the ratio of the length of deployed anchor rode to the height of the bow chock above the seabed. The greater the scope the more horizontal the pull on the anchor, and the better it will hold. Pegging 10:1 as the maximum practical scope, the table shows the average relative holding power associated with shorter scope.

 

[lord khram]

There is no edge in my reply I simply dont agree with what you are saying. As I have said the SHOT line at the hard deep is exactly that, a shot line for divers to locate the wreck and make their descent it is not a mooring line. As my last post suggests maybe it would be worth a trip down there to see what it is like as it is nothing like the diagram you have produced, and you will see your assumptions are incorrect. I had my own boat in the UK before for a time, so am fully aware of the principals behind anchoring a boat to the seabed.

 

[mgmonk]

oh... it's been so long since I visited this forum. Glad to see everyone is playing in the sandbox so well.

:nailbiter:

 

[lord khram]

oh... it's been so long since I visited this forum. Glad to see everyone is playing in the sandbox so well.

:nailbiter:

:HHGTTG:

If thats all you have to add to the discussion, pity you didn't leave it a little longer.