120 foot expedition yacht sinks off Fort Lauderdale
I'm always cautious about rushing to judgement in cases like this, however, even if all the facts are never revealed, there is at least one good lesson here. Based on the first officer's comments, the chain of events went something like this, ‘We noticed a list, the captain went below to check the bilges and reported flooding, we got the owners into the first life raft. It happened pretty quickly’.
If that's true, high water alarms either weren't present or they weren't operational. It takes more than a small amount of water to cause a vessel of this displacement to list, and as such I'd expect alarms to have sounded. Because of the water depth, over 1,200 feet, the vessel is beyond salvage, which means it's unlikely we'll ever know exactly what occurred.
Regardless of what transpired in this case, if you haven't tested your high water alarms, and bilge pumps lately, do so. The most effective, real-world test involves controlled flooding of bilges, allowing rising, preferably fresh, water to set off alarms and trigger pumps (be sure to include crash or high volume, higher mounted pumps in the test). Simply lifting the float switch to confirm the pump runs is of limited value.
A few years ago I inspected a 60+ foot vessel that was equipped with four 3700 gph electric bilge pumps. When "tested", every pump ran and the owner reported he did this periodically. However, every pump discharge was equipped with a bronze swing check valve located adjacent to the pump, used to prevent back flooding and pump short cycling. Fortuitously, while I was aboard a fresh water hose burst, flooding one of the bilges. The electric pump in that compartment dutifully kicked in and began running, however, I noticed that while there was turbulence around the pump, the water level wasn't dropping. I went on deck and looked at the discharge, and was surprised to see no stream of water. Upon closer inspection I determined that the weight of the water between the check valve and the overboard discharge was great enough to prevent the pump from being able to overcome it upon start up. This is an especially insidious problem in that the first time the pump was tested, with a dry hose presumably, it would work, however, once water became trapped in that hose, the pump would not be able to discharge water thereafter. And thereafter, if the pump was “tested” by simply lifting the float switch, it would indeed run. For this and other reasons, I have strong reservations regarding check valves in bilge pump discharge plumbing. These check valves are also prone to become seized either in the open or closed position. ABYC guidelines prohibit the use of check valves in pump discharge plumbing if it is the sole means of preventing back flooding from other pumps or common manifolds.
In testing I've done, I've determined that some check valve designs, the swing gate variety, can reduce water flow by as much as 60%.
Here are two links to articles about the sinking...
Superyacht Serena III sank on 13 nautical miles off Fort Lauderdale | Maritime News
The video interview is viewable here
VIDEO: Yacht sinks off Fort Lauderdale coast | Trade Only Today