At the beginning of each dive series, the science party decides what pieces of equipment may be mounted onto Alvin. The metal grate used to hold the equipment is called the "basket" and there are daily discussions about the exact configuration of the basket.

If the Alvin group made all the decisions about the basket, they would only have a single milk crate on the basket so they can easily move the arms in front of the sub. The ideal basket according to the science party is loaded with sample boxes, temperature probes, wands for chemical measurements, and other equipment specially designed for use on the sub. The actual basket that results lies in between the two extremes.

The basket is one meter by one meter so only a few people can work on it at one time. In the evenings, there are often several people looking on as a few scientists use hose clamps, cable ties and rubber bands to hold everything in place. The basket becomes an unofficial meeting place to discuss the next days' dive and the best order to move from site to site on the bottom. In the morning, the Alvin group will look over the science party's work and make the final touches on the basket before allowing the sub to be launched.

At the end of the dive, Alvin is moved from the back of the ship into its hanger. The science party peers anxiously at the basket, but must wait until the sub has stopped moving. As soon as the sub has been secured, the scientists descend on the basket and start removing samples while others stand back from the basket and discuss the day's dive.