Permanent Marks

My club uses LARGE plastic barrels as race marks.  Some are starting to break down and need replaced

By large I'm talking 60 Gallon ( Something like this: http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=290 422922959 )  (Much bigger than the smaller drums people tend to use on small ponds)

Assuming I can get my hands on something like this locally...what do people suggest we do for attaching ground tackle.  And suggestions for ground tackle set up?  (I believe people have welded stuff up before?)  Seems like a sensible time to review what we do.

We sail on reservoir, which does have a fluctuating water level but not tidal.

You should also use like  what we do on the sea with the tide.we use  lead line which is put onto the rope so no one catchs when the tide is slack or in you case when the water level is low some of your rope might float unless you are using chain which of course delete all of the above.