Water depth is everything... I was once tied up to a very small oil platform/gas well head in Galveston bay..  the Houston ship channel was about 1/2 mile away... We were in 10 feet of water and the ship channel is about 45 feet deep.. a giant full tanker came up the channel and I saw very little wake from it in the channel... Once the wake hit shallow water it grew tremendously... it hit us suddenly like a huge wave... I thought the bow cleat was going to yank out as the boat bucked like a rodeo bull... Jim Gano