 However, in the melee of battle, ships of the same squadron frequently blocked each other's fields of fire and collisions between them were not uncommon.Although Lieutenant-Admiral Maarten Tromp had formed a line against the Spanish fleet in 1639 in the Action of 18 September 1639, this was not a planned formation but a desperate attempt to hold off a greatly superior, but badly organised, enemy.The initial sea battles of the First Dutch War were largely indecisive melees, but later in that war Robert Blake and George Monck issued instructions for each squadron to stay in line with its flag officer.