Airship Goes to Alaska
Okay, for those of you interested, here's an update on our mechanical issues!
Yesterday morning we got in touch with Steve at of Nordic Tugs of Alaska, who connected us with Mike Svensson, a shipwright here in Juneau who was going to look at our boat and see if he could help figure out what had happened the other day. Steve said that if Mike couldn't fix it, he'd know the person who could fix it. Steve has been incredibly helpful and generous with his time and support. Thank you so much, Steve!
Mike came by the boat and we inspected the shaft seal (the thing that overheated during the drama) for signs of damage, and there was none. The shaft seal worked just as it should…there was cooling water reaching it where it should have been, and there was no sign of any damage to the bellows whatsoever.
This is the dripless shaft seal:
Not to get too technical, but for those of you who want to know and don't, the drive shaft goes from the transmission on the back of the engine, through the middle of the boat (inside, reachable/viewable through a hatch), through the dripless shaft seal (the thing that keeps the seawater out, and the thing that overheated) and then out the back of the boat through the hull (the white part on the right of that photo). As it goes through the hull, it goes through a bearing called a cutless bearing as it enters the water and connects to the propeller.
Anyway, we couldn't find anything wrong with anything on the dripless shaft seal. We brainstormed and theorized about the things that could have caused (1) the dripless shaft seal to overheat, (2) the shuddering vibration of the boat right around that same time, and (3) we also talked about the bolts that had come loose on the coupler where the drive shaft attaches to the engine transmission and whether or not that could be related or was a separate issue.
After more inspection, Mike determined that our shaft was slightly out of alignment (where it attaches to the back of the engine) by about 3/8 inch and said he could (and would like to) realign it for us. This was probably a separate issue from what happened the other day underway, but definitely needed attention. We've never hit anything or wrapped anything around the prop, but even hauling the boat out can flex the fiberglass a bit and change the alignment, so at some point, or over time, something caused this alignment issue.
We decided to have the boat hauled out by Dean over at Juneau Marine Services at high tide yesterday so we could inspect the propeller, shaft, and cutless bearing. Hauling the boat out is pretty cool. I wish I could have taken better photos, but I was busy driving the boat into a double sling between two tall wooden piers. Here's my view:
Woohoo! We're going up! (Dean said I drove that boat into that sling better than most seasoned boaters. Sweet!)
Dean raised the boat and stopped it when it was level with the walkways on either side, and we hopped across from the boat to the dock.
Getting a first look at the shaft and prop:
Dean took Airship in to the beach so we could get closer to stuff for better inspection:
The propeller looked good…no nicks, nothing wrapped around the shaft (and no evidence of anything having been wrapped around the shaft, because there was still green gunk on it…if something had been wrapped it probably would have polished it a bit in the wrapping):
Cutless bearing looked good, and there was no movement when we tried to move the prop/shaft up/down/left/right:
It felt good to be able to see and inspect all of this ourselves (and with people far more experienced than we are), up close and out of the water. We all concluded that everything looked good and we put Airship back in the water. It was kinda fun to climb across and onto the boat, get lowered back down into the water, and reverse outta there.
After we were tied up back over on the dock, Mike worked on fixing the shaft alignment. He (and Kevin, helping) did a great job and after the work was all done we took Airship out in Gastineau Channel for a quick sea test to see how things felt. The slight vibrations we'd been feeling were pretty much gone (except for a slightly louder rattling sound in the gearbox at idle). We'll do some more intensive testing on our way from Juneau to Taku Harbor in the next couple days, but I think we're good to go.
We're still not sure exactly what caused the thing to happen the other day though, which is a little frustrating (but sometimes that's how it goes). Some combination of not enough cooling water to the shaft, maybe having some kelp on the prop temporarily as we came through those following seas….giant squid? For now, all we know is that with many experienced eyes inspecting all the parts…everything looks as it should, and we've even made improvements by having the shaft realigned.
Also, this was our sunset last night (from where we are at Steve's dock at Aurora Basin):
I left a little bit of the galley window in the shot, on the left (below)…