I just had my first cup of coffee and I must admit that I had a little trouble following what you were trying to convey and ask! Depending upon how a ship wrecked when it slammed into the reef, coral heads, rocks or beached is the most significant factor in whether the coins or other cargo will generally clump together once they are deposited on the ocean floor. If a ship went down with the coins and other cargo reasonably intact and they were eventually deposited by the hull slowing breaking up or the hull breeched upon impact and the coins and other cargo pretty much dropped in one spot, they will tend to clump and therefore due to their' combined weight, be less likely to scatter North and South or Westward (as in Treasure Coast wrecks) onto the beaches and further inland. However, if a ship broke apart upon collision with the reef, coral heads or rocks and the coins and other cargo were released from their' holds (barrels, crates, chests, etc.) in a sudden surge generally in the direction of travel and deposited on the ocean floor or gradually dumped from the hull as the ship continued forward while breaking apart, they would be somewhat scattered and not be stacked or piled on top of each other and therefore be more susceptible to wave and wind action and definitely from the forces of a hurricane. It takes a long time for coral or other encrustation's to develop around coins, so therefore, they would have to remain pretty much unmoving for a very long period for this to happen. Other factors must also be considered such as the depth at which the coins and cargo were deposited on the ocean floor, the ocean floor itself (i.e. is it mainly loose sand or covered with gravel type rocks or both, or contains larger rocks, or has many coral heads, etc.), the coastline itself (are there many portions jutting out into the ocean, many bays, lagoons and harbor sized inlets) as well as the prevailing and sometimes non-prevailing (as in hurricane effects and strong weather systems) waves and winds. All of the factors and conditions that I stated, are the reasons why there is so much variability between one shipwreck site to the next!
Frank