Dive Site: The M/V Castor, Boynton Beach, Florida

Riding out of Boynton Inlet I can already see that it’s going to be an epic day of diving — it’s one of those late summer days in Florida, when the sun is out but it’s not too hot.

By  Jason Leone

The Atlantic is calm and clear blue. It’s about a 20-minute ride from the inlet to the Castor and I take the time to talk to the boat’s divemaster, John, a bit about the dive.

Our conversation is one we’ve had several times on these Castor trips. It always begins with the same question: What do you think it’s going to be like on the Castor today? It’s one of those dive sites where the conditions are a bit unpredictable; you really don’t know what visibility, current and water temperature will be until you get there. But even with all the variables, it’s worth it. Even after several hundred dives on the Castor I can honestly say that no two dives are ever the same.

The main attraction on the Castor is the school of resident goliath grouper, which weigh in at 300 to 600 pounds and live on the wreck year-round. Since we’re visiting in late September, the annual spawning aggregation is in full swing — every year around this time the goliaths gather on several wrecks in the area to spawn. The Castor is one of the largest gathering sites. It’s not uncommon to see 20 or 30 goliaths on the wreck any time of year, but during the spawning event that number can be well over 100.

As we get closer to the site, John starts to gear up. He’s going to jump in and tie in the wreck line for us. He tells the other divers on board to get ready to hit the water as soon as he’s back up from tying in. Captain Doug yells out “dive, dive, dive” and John is off the back of the boat headed to the wreck. I feed the wreck line out and get the wreck ball and dive flag overboard. As soon as that’s done I jump into my equipment.

John soon returns to the surface and once onboard gives us the conditions report. Water is clear and visibility is awesome. Goliaths are everywhere and the water temp is 82 degrees on the bottom. The current, however, is running at about 3 knots. He tells us to hold onto that line all the way down and all the way up.

As soon as John is finished, I’m in the water pulling myself down the wreck line. He certainly wasn’t wrong about the current and once I’m on the wreck, I tuck in just forward of the super structure and drop down to the deck. As I make my way toward the bow, the goliath grouper are everywhere. I am always amazed by these gentle giants and take a minute to soak in all in. I continue up to the bow and I see a swirling bait ball just off the port side. I finger crawl over to it and slowly make my way in. The baitfish engulf me, and now I sit inside the bait ball with five enormous goliaths, where I remain for the rest of my dive. The goliaths don’t swim away and the bait just keeps swirling around us. I look at my computer and see that I have 5 minutes of no decompression time left — it’s time to go back to the line. I reluctantly make my way back and ascend, thinking of how I can’t wait to do this again. 

About the site

Originally the M/V Castor was sunk in 110 feet of water; max depth today is probably closer to 118 feet (36 meters). It is 258 feet (79 meters) long and 37 feet (11 meters) wide. Many websites say that the deck is in 90 feet (27 meters) of water and that the wreck starts in 60 feet (18 meters), but the super structure in the stern has cracked off and rolled onto its starboard side, so the wreck now starts in about 85 feet (26 meters) of water and the deck sits in about 95 feet (29 meters). The bow and deck are still intact and upright, with the bow rising to about 80 feet (24 meters) on top. The M/V Castor has a north/south orientation with bow in the south and the stern in the north. 


The M/V Castor was a Dutch freighter originally built in 1970 and sailed under the name M/V Dorothee Bos. It underwent several name changes before being named the M/V Castor and in 1999 was seized by U.S.Customs after the U.S. Coast Guard found over 10,000 pounds of cocaine on board. On December 14th, 2001 the M/V Castor was sunk as part of the Palm Beach County Artificial Reef Program.

Recommended certification level:

  • Advanced Open Water and Nitrox
  • Deep Diver Specialty or equivalent experience
  • Wreck Diver Specialty or equivalent experience
  • Experience diving in strong currents is also recommended.