A single piece of sand can cause them to leak. My Zodiac had a different type of scupper, but if I left the boat in the water without the plugs in it would fill until it reached neutral buoyancy. Put the scupper plugs in. If the boat doesn't have a set, buy a set.
Hmmm...fly fishing from an inflatable boat. What could possibly go wrong? "Sir, that is an interesting place to store flies attached to the side of the boat, not on your hat." "Well the clients keep catching the boat, which is better than me!" (Yeah I might have screwed up a few casts myself and hooked just about everything around, including myself. Barbless hooks make removal easy though LOL)
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