Next, you will select the seats, and then add the boat to your selection. Then, you can join the two objects into a single object:
On the header of the Properties window, select the Object button. It has the orange cube. It's highlighted in blue in the following image.
Use the button shown at the bottom of the following graphic, in the Properties window, to change the name to Seats. Type it in and press Enter when you finish.
Select the boat. Change the name to
Boat
.Save the Blender file.
Select the seats again with the RMB. Then, press the Shift key when selecting with the RMB to also select the boat.
Press Ctrl + J.
The seats and the boat are now a single object. Now look at what the name is.
Look at the Material panel in the Properties window. Note that the properties of all three materials are listed, since both objects have been joined.