Right now I’m full of anger with myself. Looking back, I didn’t do enough.
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?
Kim
Your blog’s are nothing if not an education! I applaud your bravery in writing this article and laying bare your trials and tribulations. We actually have a saildrive, which although does not have the same sort of gland, brings a whole different sort of challenges. Chin up. you will soon be back on the water and enjoying the feel of the breeze in your hair!
Take care
Steve
Thanks for you comments Steve. They got our generator working yesterday and they’re working on our engine now. Our outboard was fixed yesterday so… things are coming together. I think they have a plan for the stern gland and once that’s sorted we’ll be able to hit the seas again! Big smiles!
Kim, we know exactly how you feel and there are so many boat owners out there in the same position that don’t know enough. I am one of them I fully admit. Slowly I am learning by doing.
Just want to say what a wonderful clear website you have that is more than a pleasure to read. See you soon.
My boat has got a sail drive – and I knew nothing about stuffing boxes, so this is brilliant information. I really hope you manage to get it all sorted without it costing too much. I will certainly be making a note of this for when we buy another boat, to make sure I fully understand what needs to be done if we end up with one of these!
Hope it all turns out ok for you!
Viki x
I know the feeling the problem with a “new” boat is that very often you don’t know what you don’t know, so it is a continuous learning experience and sometimes an expensive one.
May I suggest that if your shaft seal is damaged you should consider an alternative system such as those by Deep Sea Seal or the PSS Shaft Seal … These do not rely on stuffing but use a carbon bearing that spins against a stainless steel face. The carbon/stainless steel faces are water lubricated by the water in the shaft tube and are so highly polished that there is no leak. There is no possibility to damage the shaft and is virtually maintenance free and self adjusting. The only thing you need to do is to remember to “burp” it by letting a little bit of water in when you launch the boat. I have one on my own boat and it is really hassle free.
Wow Patrick…those seals sound so much better! We just put new packing in the stuffing box and tomorrow when we run the engine we’ll look for our drops of water. Perhaps longer term we’ll think of a different seal option. You’d think that with all the technology we have they’d have a better solution that the one we have. It seems so odd that you have to ensure that water comes INTO the boat!
Thanks for being so frank in your reports Kim. I understand fully the overwhelming number of things you have to take in when going through the process of boat purchasing. At least by writing about it you are creating a valuable resource for some of us who may follow in your wake. Keep doing what you do, it’s a great read!
I have to admit I know how you feel. I too took the stuffing box for granted and did not do the due diligence needed to secure the safety of my boat. Upon boarding her one morning I found a foot of water inside the cabin. After manually pumping all of the water out (as the bilge pump had accidentally been switched to “manual”) I quickly realized that the water was coming from the stuffing box. Tried to tighten but wa corroded tight. Ended up replacing and constantly checking now. Hard lesson but effective.
Thank you for sharing Bob 🙂
As a person who has installed/owned and used all three mentioned stern glands. Here are my comments:-
1. PSS:- very reliable but concertina neoprene pressure section has to be changed every few years for peace of mind. Any bearings behind it may require extra cooling/lubrication.
2. Deep sea seal:- very reliable but as it gets older you have to use a squashed Big mac plastic straw filled with waterproof grease to sqeeze into it to stop wear and leakage, a really fiddly job. AS above any bearings behind it may require extra cooling/lubrication.
3. Original greaser type with packing, infinitely reliable, do the regular maintenance as specified don’t change it and waste your money.