As you may have guessed from the photo, I like to sail. I have an F-25 trimaran "Gazelle" that was built by the previous owner from wood. I've sailed from Puget sound to Desolation sound in her, and near Vancouver we outran a commercial fishing vessel once at about 13 knots :) Sailing seems to be a mix of fun times, slow times (when the wind dies), exciting times (when the wind and swell are up and you have to pay attention), and moments of pretty much sheer terror. Yesterday was one of the latter times, and I'm still a bit dazed, so thing of this post as therapy :)
Shilshole has been rebuilding its slips for a long time, so every once in a while they ask us to move our boat to a new slip. Yesterday was such a day and I didn't have much time so I didn't plan on a lot of sailing. My cousin Casey just arrived in town, so I took him with me and the two dogs just because. My cousin hasn't sailed before, but we were just changing slips so it didn't matter much. Of course once you're on the boat you have to go sailing! On the way over I was concerned the wind was too strong for casual sailing with a newbie and 2 dogs) (it was 10-20kts and a bit gusty). We went ahead and motored out to the sea lion cage so the inlander could see the sea lions, and I took care to make sure we were all wearing vests and gave my cousin a cursory "push this button to start the engine" lesson just in case.
Once outside of the breakwater the sound was pretty flat and it was pretty with a good wind, but not too rough, so of course I decided we may as well sail for a couple minutes so my cousin could see what it was like :). We started out well, on a beam reach at about 7.8 kts. Everyone was having fun, although the dogs on the trampoline were looking a bit concerned about the spray. I showed my cousin how to steer a bit, and of course we had a bit of the tiller-moves-the-wrong-way problem that people new to tillers always have. (You move the tiller to the left to go right, etc.)
I headed up some trying to get a feel for the wind, and we slowed to 4 kts or so, still on a port tack. I was sheeting in the Genoa, and suddenly *BANG*. The sails and mast were all over the place (but still up), the dog's were in Casey's lap and things seemed to be a mess. I knew I had to get the pressure off the sails or we'd lose the rig, so I grabbed the tiller and headed head-to-wind and turned on the engine (Its an outboard, I'd left it down so that my cousin didn't have to figure it how to lower it in an emergency.) I asked my cousin to keep us pointing into the wind and went roll in the head sail to relieve the pressure.
I could see that the port shroud had failed, and the port shroud/backstay (we have two shrouds running out to the back of the ama's) was loose, swinging on an additional tensioning line. The mast was flopping to starboard since nothing was really keeping it to port, and the mast step was twisting (the mast is deck-stepped since its trailerable).
Being inexperienced, Casey of course pushed the tiller the wrong way and we started to drift onto a port tack, backwinding the genoa when I only had it half way in. Of course he then pushed farther. (Casey did wonderfully, he'd only had about 10 seconds of steering experience before everything died). I could see us jibing and losing the rig completely, so I grabbed the tiller and revved the engine up. Casey's inexperience was a bit fortuitous though since the starboard rigging was OK, and on a starboard tack the mast was pretty tame. The mast still bounced a bit in the mild swell, and I had Casey tighten the adjuster that was attached to the dangling port shroud/backstay. This kept the mast tame and Casey held the course while I finished rolling up the genoa.
Our main furls by rolling around the boom (the boom spins). Normally this is a mildly cumbersome process because the bolt rope doesn't slide well (it and the track are old), and the bolt rope wants to crowd around up against the mast. This time I got the main down in about 5 seconds! I didn't even pause for the small batten at the top (a batten is cheaper to replace than a mast). Interestingly we still had a little wind on the main, keeping the load off of what was left of the port backstay/shroud, but not enough wind to keep from lowering it.
I felt more comfortable once the sails were down, and we calmly returned to the marina and tied up in our new slip. I had been worrying about the mast falling on the cockpit or the dogs (its kind of amazing the number of things I was considering in the middle of the disaster), and had wondered how Casey would call a mayday if something had happened to me, but it was a lot better after the sails got down. Another boat passed by while I was trying to get the load off the rig, but they were out of shouting distance, and they probably thought we were just returning to Shilshole and didn't see our missing rigging.
Once at the dock things were much tamer. We tied the dogs to a cleat on the dock and removed the boom/mail sail and the genoa (its on a bowsprit in front of the jib/headstay. The dogs were really patient, but eventually they got bored and started playing and "Brighty" pushed "Scooby" off the dock. He was still wearing his vest though, so I just yanked him back up by the strap. He almost immediately got pushed in again, so we separated them and then Casey took them to the car (back at B dock). I met up with Casey just when I got done securing the boat.
We found that the port shroud had corroded inside the fitting at its base. This can happen because rain (and saltwater) drips down the shrouds into the fitting and its hard to dry out. I think that after that failed, then the port backstay failed with the additional load. It has a heavy steel u-bracket and clevis pin. The bracket was bent and the pin pulled out. I have no idea why the tensioning block and tackle didn't also fail, its mount is weaker. My best guess is that either the line slipped through the cam cleat with the additional load, slowing the sudden shock, and/or the mast moved enough after the shrouds failed to relieve the load on the sails.
Later we came back (after showing Casey the Ballard locks and let him take the dogs home, Shilshole didn't provide a hose at our new slip so we had to come back to rinse the boat/engine.) My sister found a bolt near the bottom of the mast. I looked up, but it was a big bolt and couldn't think of what it could be. Then she found a 2nd, and then a 3rd. The 3rd was the clue because it was under a plate at the bottom of the mast. Only one bolt remained holding the mast to a plate at its foot. The other three had been pulled straight out of their aluminum threads.
We also found all the pieces of a clevis pin (spring, ring, tie & pin) from a spare line. It had been clipped to the mast, and I'm guessing that somehow the sproing from the snapping line caught the ring and disassembled the pin. I have no idea how with all the bouncing of the boat the pieces all stayed near the mast, but I was able to reassemble the part with no missing pieces or problems.
We temporarily secured the mast by running additional lines such as the spinnaker halyard and (once it was down), the main halyard to convenient points on the port ama. They won't stand a high load, but without the windage from the sails that isn't a big problem We also put in some new bolts at the bottom of the mast foot, although it'll need to be replaced.
Some lessons I learned:
I'm so glad that the seas weren't rough that day!