I found this in the above listed link.
So, if 180 days engine time can be used for this deck license then the 90 days recency can be engine time? On the appropriate tonnage vessel?
§ 11.410 Requirements for deck officer endorsements for vessels of not more than 1600 gross tons.
(a) Endorsements as master and mate of vessels of not more than 1600 gross tons are issued in the following tonnage categories:
(1) Not more than 1,600 gross tons;
(2) Not more than 500 gross tons; or,
(3) Between 25-200 gross tons in 50 ton increments and with appropriate mode of propulsion such as steam or motor, sail, or auxiliary sail.
(b) Experience gained in the engine department on vessels of appropriate tonnage may be creditable for up to 25 percent of the service requirements for any mate endorsement in this category.
© An officer’s endorsement in this category obtained with an orally-assisted examination will be limited to 500 gross tons. In order to raise that tonnage limit to 1,600 gross tons, the written examination and service requirements must be satisfied.