Size Matters, for SMB's

Understanding Surface Marker Buoys: Size, Visibility, and Inflation Guide

Why SMB Size Matters for Diver Safety

Your Surface Marker Buoy’s primary purpose is ensuring dive boats can spot you from a distance. However, many divers don’t realize how size affects visibility over distance.

Inflation Techniques and Surface Performance

Underwater Inflation Facts

• Full inflation underwater is possible and often beneficial
• Inflating at 10m depth provides optimal results – air expands to double volume at surface
• Partial submersion at surface is normal and necessary for stability

Surface Visibility Mathematics

• An 1.8m SMB appears only 1cm tall from 100 meters away
• This reduction follows the Inverse Square Law
• Real-world testing confirms these visibility calculations

Choosing the Right SMB

Key Selection Tips

• Avoid selecting “small” SMBs
• Choose larger sizes for maximum visibility
• Remember: A smaller SMB defeats the safety purpose

Note: SMB = Surface Marker Buoy, DSMB = Delayed Surface Marker Buoy