In-Build M25 Explorer By Aegean Yachts A new tri-deck range has been initiated at the Aegean Yachts company called the M25 Explorer. The first hull is actually under construction utilizing a steel hull. As the model name suggests, it is a 25-meter vessel making it 82.5-feet long. The M25 will be the smallest of the range as the others are planned to be 37 and 48-meters respectively. While the first hull is being fashioned with a steel hull the yard suggests that all three model sizes can be built from steel or aluminum, dependent on what the owner prescribes.