Camera gear coverage from water can be excluded in some situation under Business Personal Property on a Business Owners Policy. That's why you need Inland Marine coverage as an Add On!
BOP Exclusion reads:
(1) Property Not Covered "Flood, surface water, waves (including tidal wave and tsunami), tides, tidal water, overflow of any body of water, or spray from any of these, all whether or not driven by wind (including storm surge);"
(2) Property Not Covered. "Property while waterborne. However, we cover property while aboard vessels on inland waterways when the waterborne transportation is incidental to the land portion of the journey;"