Super Mario Sunshine/Pinna Park blue coins

Ship #1
From the ride staircase that leads up to the two rocking ships, jump across to the second ship and ride it up to the left (stand on the front of the ship). When it has enough momentum to reach the platform above grated box, stand near the front and do a turning jump, then hover over to it.

Ship #2
On the first rocking ship (closest to the park entrance), ride the back of the ship up, hop on it, then hover over to the blue bar that acts as its suspension. Slowly walk over to the opposite side to reach the coin. Alternatively you can attempt to ride the front of the ship up to the coin, however it's much harder.