I didn’t pay enough attention during my Diesel Marine Engine Course and I didn’t research the most important things to know before taking over a second hand boat.
Yes, we had a 35’ Moody sailboat for a couple years but the systems contained within where simple. In fact, everything was relatively easy. We did the standard maintenance ourselves and then paid someone to give the engine a look over every year.
Furthermore, we never ‘wintered’ the boat as we used it year round. We simply took good care of her and she took good care of us. We’d bring her out of the water, do the antifouling, change the anodes and so forth. Furthermore, when we received our boat, she was old but in good shape.
Our small thirty year old 35’ sailboat was a walk in the park compared to our eleven year old 56’ Oyster
Looking back and using hindsight, we should have found our own marine engineer, skilled in the electrical and mechanical aspects of diesel engines, and flown him or her out to the boat to inspect before purchasing. We should have done that in addition to getting the $2000 marine survey we paid for… but then again, we needed our money to buy the boat.
And then, in addition to that, we should have connected with some full time live-aboard cruisers and if money was no object paid someone to fly out to the boat and look over the whole thing – to go up the mast and look at the rigging, to check out the steering and propulsion systems, to go through the inventory and make sure that all the rigging was on the boat, to look at the expensive things to ensure they’re in good working order.
Unfortunately, for us, money is an object and we have a limited supply of it
We would have still purchased the boat, as we are totally in love with her, but at least we would have known what needed to be done to maintain the integrity of the systems.
Instead, we’ve been sailing and motoring around all summer with seriously congested engines, dangerous rigging and something so terrible that’ I’m embarrassed to admit it…
We’ve been sailing around the Mediterranean all summer with our stern gland packing box locked closed (I’ll explain what this is in a moment).
I can just hear all the captains of the world snickering thinking, ‘what a bunch of idiots. They know nothing. They’re going to sink that boat…’
Fortunately for you, I’m okay with having the sailing world laugh at me.
If I don’t write down our mistakes, what’s the sense of me writing anything?
Yes, most of our experiences are amazing and those are great to share, but it’s the massive errors that need to be shared. If we all share our good AND bad times, perhaps we can help others to avoid feeling like I feel right now! (I feel like the biggest idiot in the world)
Let me tell you about the stern gland on a boat
If you have an inboard motor that turns a shaft attached to an external propeller, that shaft will pass through a stuffing box, or stern gland. It is used to cool and lubricate the shaft while preventing water from coming into the boat.
On our boat the stuffing box doesn’t look anything like a box, but rather a set of round shaped clamps around the shaft (see top picture). Inside the ‘box’ is a thing called packing that really looks like wide waxy rope (see below picture). In our stuffing box, we have three lengths of wide rope set in a circle to be packed along the shaft.
The way it works is that you compress the stuffing box, and packing, so that enough water from the outside comes in to lubricate and cool the shaft, but not so much to sink the boat!
Depending on where you get your information, I’ve read that the drip rate should be 1 drop every minute to 1 drop every hour while the shaft is in operation and it shouldn’t drip when the engine is off.
Yes, the water does drip into the boat and it’s designed to do so
Aside from the stuffing box there’s also a grease aspect. On our boat, we manually turn a handle to force grease into the stern gland (see above). You’re supposed to do it every day if running the engine heavily or once a week with moderate use. You turn the handle until you feel pressure.
Faithfully, we’ve been doing this job but in our ignorance we didn’t witness the water drips. In our Oyster manual, it says that we need to see it drip once an hour. Can you imagine putting your head in the hull as you’re motoring along waiting for that one drip?
Needless to say, our stern gland was not dripping but we didn’t realize the implications
Previous to getting our boat, someone must have closed the packing box tight to eliminate the possibility of water entering the boat. If you’re going to leave your boat for a long time or when you winter your boat, you’ll want to tighten the box.
HOWEVER, YOU NEED TO WRITE YOURSELF A NOTE TO REMIND YOURSELF TO UNTIGHTEN IT AND MAKE SURE IT’S WORKING.
When we picked up the boat in Palma, Mallorca with our professional skipper, our broker asked if we had questions. We spent a few hours figuring out the mammoth electronic breaker board, finding the grey and black water tanks and outlets, pulling out all the safety equipment and so forth. Our heads were a mess.
Both hubby and I were excited and terrified at the same moment. Just looking under the floor boards in the saloon, we found 9 truck sized batteries running all sorts of things. We had a generator, engine, inverters, battery chargers, heating system, fridge and freezer systems and have you noticed I haven’t even mentioned the whole ‘how to sail the boat’ aspect?
I’ve come to realize that sailing the boat is the easy part!
Anyway, no one thought to check the stuffing box.
Yes, we turned the greaser like it said for us to do and we did this faithfully. I’d often look for a drip or water in the bilge and I think I did see it…but I didn’t understand what I was greasing or why water needed to drip.
So…all summer we’ve been overheating our propeller shaft
It’s a miracle we didn’t burn the boat up or completely destroy the shaft. When we pulled out our packing, it came out black – it’s burnt to a crisp. As I write this I’m still not entirely sure if our shaft is okay. We’re having it sorted out today (I think)! Thankfully, we have some amazing engineers helping us out 🙂
If you have issues with your stuffing box, the results could be catastrophic. We’re talking about a broken shaft or even massive amounts of water entering the boat.
All that being said, I’m not the only idiot out there…
As a side note, while researching information for this article, I discovered that I’m not the only person in the world that didn’t understand the existence or importance of a stern gland. Apparently, it has a very bad reputation for be an inferior piece of kit but that’s because the majority of boat owners don’t know how to properly service it.
Many boat owners keep pumping the sterngland with grease and completely fail to realize the importance of tightening the unit (supposedly 3 times/year) and repacking the stuffing (or rope).
Apparently, old packing material is the number one cause of problem leaking, and shaft wear and damage, as noted by Bears Marine Development (boating hardware specialists).
If you don’t spend the $20 on new packing the result could be $1,000’s on a new propeller shaft
It’s recommended to change the packing in the stuffing box every 2 years or sooner if there’s excessive leaking. Don’t just tighten the packing box!
So…come on – are there any brave souls out there that want to admit that they haven’t changed their packing in a while?