Do you already have speakers on the deck? Are they connected to the same receiver as the laptop?
Then you only need to control the laptop playback software with your phone. You can do that with most of them with the right app.
If don't have anything on the deck then it depends on how much area you need to cover, how loud you want to play, and how much money you want to spend.
You could just connect a BT transmitter to the laptop headphone out and use any BT speaker.
You could use a Sonos or Denon Heos speaker on the deck. Denon has a battery pack for their smallest speaker so it would not have to be plugged in.
You could use a Sonos ConnectAmp or HeosAmp with any pair of passive speakers.
If you needed more sound you could use a Sonos...