Unfortunately there has been a number of accidents and incidents involving divers who surfaced without using a D-SMB. These can include divers drifting for miles because they failed to get the attention of their dive boat upon surfacing, or divers being smacked by powered pleasure craft on the surface.

One of the most tragic incidents involved singer Kirsty MacColl in December 2000. (It is probable in this instance that the use of a D-SMB would not have saved her because the boat was being driven in a restricted area in an inappropriate manner.)

And then there are those occasions when deploying a D-SMB by an untrained or out of practice diver can pose some common but preventable hazards, such as getting dragged to the surface.

The emphasis on when and how you learn how to use a D-SMB differs - it depends on which agency and instructor you train with. However anything that can safely aid training is always welcomed by the community. I was therefore pleased and intrigued by AP Diving's latest offering.

Brit manufacturer AP Diving has long been renowned for making high quality D-SMBs that give the diver a choice of filling methods. (0.1 litre DIN 'crack' cylinder, inflation using a purged regulator, inflation using an 'Easifil' low pressure inflator hose).

AP Diving has just released their latest buoy; a Training Surface Marker Buoy. This D-SMB is identical in design to the rest of the AP self-sealing D-SMB range. It is just much shorter, and at first glance is probably the perfect sized D-SMB for a Minion.

For those of us who are not diving minions, this two litre capacity buoy allows the trainee diver to practice deploying their D-DMB multiple times in confined and open water without seriously depleting their gas supply. The D-SMB is inflated by inserting a regulator into the mouth of the buoy. (Alternatively this training D-SMB can come with a 0.1 litre DIN 'crack' cylinder or an 'Easifil' low pressure inflator hose so that the trainee gains the benefit of learning three methods of inflation.) Once inflated, the mouth of the buoy then self-seals with a baffle to prevent gas loss from the buoy when it reaches the surface. Deflation is achieved with the dump / over-pressure valve.

The only thing I am not that keen on? Ironically, the colour. Despite our best endeavours, we can sometimes get distracted. I can foresee an instructor or a trainee absent-mindedly picking one of these up and subsequently attempting to use it it anger on a dive and finding themselves rather nonplussed, wishing they were the size of a Minion.