As IMO's Ballast Water Management Convention (BWMC) creeps ever closer to its tonnage percentage target, the practicalities of how it will be managed by owners and operators seem to be no clearer. That's how it seems from my desk, anyway.

First, a status update. By mid-June, Peru's ratification documents will have been delivered to IMO secretary-general Kitack Lim (they are at Peru's London Embassy awaiting a window in the ambassador's and Mr Lim's diaries) boosting the percentage by 0.04 per cent: not enough on its own to breach the 35 per cent threshold, but IMO's end-May monthly reanalysis of global tonnage could also have an impact – one way or the other.

There was one definite ratification in the past month – Saint Lucia – although its tonnage is too small to make any impact on the global total. And what of Panama, which seemed to be on the brink of ratifying earlier this year? No more news has reached me about that.

What has reached me, however, are stories of technical trials and tribulations. I commented last month about an account of poor performance, offered by a director of a leading ship manager in a presentation about his experience of operating a large number of systems. When I sought further detail, none was available. He had probably said a bit too much, but the cat was out of the bag.

Off the record, I have heard a number of tales that echo his experience. I have been told about systems that are said not to match their performance claims, of retrofit contracts that may not be as extensive as reported, of type-approval tests being commissioned from laboratories where systems are most likely to pass – with the suggestion that there is no common performance standard among these centres.

Like the proverbial swan, it seems that there is a lot of frantic paddling going on out of sight while the view presented to casual observers is of graceful movement by a bird ready to take flight.

I am wary of stretching that analogy too far, but one development that would put wind under the bird's wings would be progress towards US Coast Guard type-approvals.OceanSaver has joined the list of those who hope to be among the first to take off in that direction but a report last month underlined just how far behind schedule this programme has fallen.

By now, a flock of systems should have been assessed, giving sufficient data for the USCG to consider more stringent discharge standards. Back in 2012, a Phase One ballast water discharge standard (BWDS) was set – it is the same as IMO's – with an expectation that a tougher Phase Two standard would follow. This was to be developed using the experience from Phase One type-approvals and a review of the practicability of elevating the requirements was scheduled to be carried out by 1 January 2016.

That review was carried out and its conclusions were obvious: there are no credible sources of data, its authors wrote, on how closely ballast water management systems meet current USCG discharge standard so plans to introduce a more rigorous standard cannot yet be implemented.

Three cheers for that, some would say, and I can understand that view. But we should not welcome all unintended consequences. From what I hear, one of the unintended consequences of BWMC coming into force may be to expose the realities of what is currently just gossip. That serene swan may yet turn out to have clipped wings.