For the purposes of the lighthouse database, it could be argued that it is not necessary to define or develop these definitions, but inevitably, the overlap of interest in lighthouses and lightships (there are many books having this title) means that we must apply some consideration to this topic.
The most obvious equivalent to a lighthouse is a lightship (or lightvessel). A definition is readily forthcoming that is in direct parallel to the lighthouse and is given in Table 2. However, there are other structures that do not fall into this category. We summarise these as LANBYs, lightfloats and lightbuoys. Again, definitions are given in Table 2. Whilst, there is no doubt that there is a clear distinction between a lightship, and a LANBY, it is not so clear about the differentiation between lightfloat and lightbuoy. We consider there to be very little difference between them, but we do allow the possibility of them having a different design and construction.
The photo above shows a moored, lit lightbuoy of the cardinal type. This means that it indicates a point of the compass. In this case, the two upward facing arrows on the top indicate a hazard to the north of the buoy. They are always black and yellow. It has a solar-powered flashing light.
This photo shows a lightfloat with a solar powered flashing red light.
From Figure 1, these are examples of navigational aids that are floating, moored and lit.
When we consider all those unlit objects afloat in the seas that might be included in the term, navigational aid, there are many possibilities. Of course, there are many floating artifacts that are not navigational aids. We believe, the great majority of these can be described as buoys or marks, where the two are distinguished as follows:
A mark is defined as a floating artifact on which there is some kind of pole with an indicator of some kind (cross, arrow, triangle etc)
A buoy is a floating can (round, square or cylindrical) without such an indication.
As it is not intended to include these in a lighthouse database, it is not proposed to develop this definition any further.