Welcome Zak is a fan made episode.
One day, O.J. is going work for the Fletcher Fleet, and Zak will have to do O.J.'s work as well of his own. Then Captain Star is very impressed with Zak for doing O.J.'s work and while Zorran watches Zak doing some Star Fleet work and Zorran decided to tell Captain Zero.
Captain Zero is very angry with Zak and he was just doing O.J.'s work, so Captain Zero fired Zak and told him don't come back to his fleet ever again. Zak was very sad, so Captain Star is going to send Ten Cents to take Zak to the Lucky's Yard to be fitted with new parts and a new coat of paint. So Zak is very happy with his new Star Fleet livery and his new parts were fitted perfectly. So now he's part of the Star Fleet.
Meanwhile, Captain Zero buys Bluenose the naval tug and he became a Z-Stack and he became a 3rd tug of the Z-Stacks.