Here's what's happening at Disneyland Pirates. I'm a former Pirates cast member and I was working there while they tested three new prototype boats (of the same design) last year.
First of all, I believe that the fleet currently in service is at least the second set of boats since Pirates opened in 1967 and more than 20 years old. The original boats had five rows and these have six. They are made of reinforced fiberglass with an inner metal frame to which are attached the four guide wheels on the side of the boat. It is these guide wheels that are in contact with the submerged metal guide rails that form the "flume".
The WDW Pirates boats are based on the Disneyland Small World "Rubbermaid" boats that were introduced after iasw's major refurb a few year ago. They tried these at Disneyland a few years ago, but they failed spectacularly. The guide wheels literally ripped themselves out of the side of the plastic boat. Remember, California has two drops, and our second (smaller) drop is still longer than Florida's drop, which is basically a water slide.
The current boats at Disneyland are very durable, but with their age are taking on water. During the past few years they have added first one and now two vacuums on the unload dock concealed in dockside crates to vacuum out the boats, mostly rows one and six. Management has repeatedly monkeyed around with the seating configuration to try and optimize the maximum number of guests versus the minimum amount of water. It used to be 3-4-4-4-4-3. Then they reduced the back row to two, then the front row to two, then they (disastrously) tried three in every row (suggested by an efficiency expert) which tanked the capacity numbers. Last I heard it was 3-4-4-4-4-2, but that may have changed. Remember, the target is 2700 people per hour.
I worked some overnight shifts with the prototype boats last year. They were tested empty and with "water dummies", which are the large plastic water tanks designed to "sit" in the seats and mimic the weight of actual passengers. These are used on everything from Pirates to Big Thunder to Racers. There are also some tests with sandbags. They tested everything from the load belts and sensors (which are very important) to the flow over the flume pumps (around 30 zones as I recall) to the evac brakes to the drops and lift.
I assume these prototypes were the model for the seven boats currently in circulation. We were told last year that we would receive new boats in phases over six months or more. They actually have channels that allow water to flow to the back of the boat between rows five and six and empty back into the flume through a one-way valve when the boat goes up the lift. That part of it seemed to work well in testing, although I heard there were other problems.
We were promised new boats for 10 years. It became a famous myth in New Orleans attractions--kind of our local Loch Ness Monster or Bigfoot!
I hope these new boats work out--they are long overdue. Pirates has a great crew and they sustain the high capacity through their blood, sweat, and tears. Between the backdoor entries, which include handicapped, readmissions, and Guided Tours/VIPs, and the extended queue which is all temporary rope and stanchions, it is very frustrating and difficult to manage, despite the dedication and camaraderie of the crew. There are some great people there and they are not appreciated as much as they deserve. Management are largely a bunch of humorless trolls who got promoted by learning to play the game.
Pirates is a magnificent attraction and beloved by those who work it--but there's a high burnout rate. Even Bruce, the famous pirate with a real pegleg, bailed out. Hopefully the new boats will work out--they are long overdue.
Trivia: The prototypes last year (and probably the new boats in service) were made in China. Shanghai Disneyland's Pirate boats are being made in Tustin, California, 10-15 miles from Anaheim!
That's what I currently know. I was last in the park a month ago. Whenever I go again I'll try and chat up some Pirates and see if I can learn anything new.