The method that McGarrett gets from the USS Knox (DE-1052) to the Cochrane (DDG-21) is called highlining on the bosun's chair. It is used to transfer people or small cargoes between ships at sea. It involves the two ships matching course and speed as closely as possible, firing a line and sending the person across.
Wo Fat's yacht was operated by a Honolulu-based operator Seaflite Inc. The rather fast craft is a Boeing Jetfoil 929-100 hydrofoil. It's top speed is a claimed 51 M.P.H. Since it floats above water it's speed is not measured in knots. It is actually a passenger ferrying vessel (151-400 pass. cap.) and not a yacht.
Among the ships shown at Pearl Harbor are the USS Berkeley (DDG 15), The USS Ouellet (DE 1077), The USS Knox (DE 1052), and the USS Cochrane (DDG 21). McGarrett is shown onboard the USS Ouellet and transferring to the USS Cochrane to meet the admiral.
This episode (and season) mark the third time that the opening theme song was re-recorded to sound noticeably different. (The first time was at the beginning of Season 5, the second time at the beginning of Season 7).
The U.S.N. Destroyer Escort is The U.S.S. Knox (DE1052). McGarret was actually aboard the vessel filming at open sea. Shortly after the filming, The Knox was reclassified as a Frigate and reassigned from its base at Pearl Harbor, To Japan.
Ref:navsource.org