Six hundred timber piles are to be driven to a depth of 40 ft in sandy silt below the water table. The soil has a we unit weight of 105 pcf. Compute a representative ultimate pile capacity if minimum tip diameter is 8 in and minimum butt diameter is 20 in. Suggest a type and size of pile-driving hammer, using the Engineering News Formula. The pile Design load is 50 Kips. Justify your choice and describe what problems you might encounter.