This technical session is all about not ignoring the signs when you are talking maintenance and not to rely on the theory of recurring miracles as a maintenance method.

Setting the scene

By the time we left Darwin, Australia, on 5^th of September, both Suz and I were very keen to start moving again. We were also pretty confident we were in good shape maintenance wise, having had plenty of time in Darwin to address all the various issues outlined in the last technical session on the blog. I had noticed the odd flake of rust starting to appear in the engine room but assumed (mistake number 1) that this was just a sign of an 11-year-old boat. I did open up the enclosure up top of the pilot house to have a look at the exhaust and muffler, but the insulation all looked fine and I thought no more about it except to say to Suz we should probably renew the insulation when we get to Brisbane and check the exhaust system while we were at it.

The next two weeks were spent exploring the Coburg Peninsula, while on our way to rendezvous with friends at Nhulunbuy on the far east of the top of the Northern Territory.  On the way ‘Opal Lady’ performed faultlessly until the 20^th of September. That evening we had anchored at a place called Cape Stewart. We knew it wasn’t a great anchorage as it was quite exposed but we had no other real option. That night we were hit by strong wind against current resulting in us being beam (side) on to 2m seas which made for a very rolly and uncomfortable night. We had one of our flopper stoppers out, but it was too rough for even this to have much effect. I was also concerned that it was so rough that we were seeing the poles supporting the mast (from the roof of the pilot house) flexing significantly and whipping back and forth, which we had never seen before.

After a miserable night, which we agreed was our worst anchorage, weather wise, so far in our travels, we hauled the flopper stopper up only to find 2 of the shackles joining the chain to the flopper stopper itself had gone. This is despite the fact these shackles are spot welded to prevent this happening which gives an idea of the forces involved the previous night. We hauled anchor and started to head off to our next anchorage at Galiwinku. Soon after we started cruising Suz came up from the galley to let me know that we had no water. She then went below and came back up to state that not only did we have no water but the water tanks which had been nearly full, were almost empty. The pump was off at this stage so we didn’t destroy it, while Suz checked all internal taps and fittings to see where the leak was. Nothing was amiss and the bilges were clear. We have a rule while travelling about not going up the front or up top if the weather is anything but dead calm, so we agreed to carry onto our next anchorage, Galiwinku, resolve the leak and then make water.

When we got to Galiwinku I went up top and could see signs where water had leaked out from the external tap fitted below the exhaust enclosure. I assumed the fitting had broken inside the enclosure and took off the side louvre section – the problem became immediately evident. The violent movement of the mast, to which the exhaust is attached, had been the final straw and a hole had blown out of the muffler and the hot air from the exhaust had melted the water pipe, hence the loss of water. In retrospect losing the water was most fortunate as otherwise we would not have known about the hole; the increase in noise from the muffler was not that great and we would have gone on our merry way oblivious to the sad state of the muffler. The enclosure also contains all the wiring and cables for the hoist, the radar, tv, satellite, anchor light and weather instrument so the thought of potentially losing all of that was not a happy one.  Not good.

Solving the immediate issue

We were both aware this was a potentially big problem to experience in a very remote area, so after a troubled night’s sleep we got up early to tackle the issue. First, we removed the top section of insulation whereupon the magnitude of the issue became apparent.

It was clear that the muffler was completely shot and appeared to be only held together by the insulation. We were approximately 120 nautical miles (220km) from Gove at Nhulunbuy, which was our next destination and the nearest place with any sort of facilities. Nhulunbuy has an airport and is a mining town so we knew if we could make it to Gove, we would be able to sort things out, even if it took some time.

The first problem was how could we put together a solution so we could travel to Gove and secondly how could we protect all the essential cabling previously mentioned. Firstly, I reinstated the top level of insulation but repositioned it so that the main hole in the muffler was covered. While I did this my brilliant wife remembered we carried 2 fire blankets. We also carried wire and some steel cable ties. With the first fire blanket we McGyvered a solution to prevent any hot exhaust air escaping into the exhaust enclosure.

Once that was done, we used one of the grills off the enclosure and the other fire blanket to protect the cabling. All this took about 2 hours and were ready to go! This solution worked brilliantly and although we checked the exhaust every 3 hours to stay on top of any potential failures, it held together and 3 days later (we were day hopping along the Wessel Islands), we thankfully arrived in Gove on the 24^th September after a trouble-free run.

Understanding the problem and gathering the resources

Once in Gove we needed to understand the magnitude of the failure. Although obvious the muffler would require changing out, we needed to understand what else may be involved, what other parts we would need and where I could get some assistance from.

We had some large industrial garbage bags on board so armed with these I started to pull the old insulation off. Very quickly I saw that the muffler was completely rusted out and it was a wonder the insulation had held it together so well. As the insulation was taken off each piece was numbered so the various pieces could be used as a template for new insulation to be made up. Once the insulation was off it could be seen the muffler was broken clean off at both the upper and lower ends.

The central section just pulled out and after cleaning up all the rust the next step was to see how easy it was going to be to remove the flange sections. Quick answer was not at all as at both ends the nuts were completely rusted on. Also the silver flexible exhaust air sleeve for removal of the air pushed up the exhaust annulus from the engine room was also on its last legs. 

After cleaning things up there were now 4 key priorities (as recognising we were in a very remote part of Australia logistics was going to set the timeline for repair)

• Order a new muffler
• Find a local fabricator/mechanic that could assist with removal of the flanges and re-installation
• Order new insulation
• Order new flexible exhaust air sleeve

The muffler

After speaking to the Australian Nordhavn rep, Peter Devers in Brisbane, he connected me with Justin Brown at PAE (Nordhavn) in Dana Point, California. Justin swung into gear and although it was frustrating waiting for info, Justin did a great job of sourcing the muffler and negotiating price and freight. One of the things about Nordhavn is they have records of all their builds so it was relatively easy to go back to when Opal Lady was built, identify the exact part and go back to the manufacturer and order the part, OR SO I THOUGHT. The muffler had to be built and finally left the US on Friday 18^th October. By the following Friday it was in Darwin and arrived in Nhulunbuy 11 days after being picked up in the US. DHL organised the freight and I was impressed by both the speed and level of information given by them on the muffler’s progress. Excitedly I picked the muffler up from the shore and once back on the boat carefully unwrapped it. Immediately I saw there was a problem. The old muffler flange had 8 holes and was a 4” diameter hole, the one sent to me was a 4 hole flange with a 3” diameter hole.

So what had happened? The muffler that had been ordered by Justin matched the part number in the manual I had for Opal Lady. I suspect that when the manual was being made up it was altered from a previous model which makes sense, but clearly the muffler was for another boat, not Opal Lady. Some how this snuck through whatever checks are done before issuing the manual. We have found, over the time we have had Opal Lady, a number of these errors.

At this stage Josh Ison from Harco, who make the mufflers, was involved in coming up with a solution. I have to say he was very good and very clear on what he needed to help expedite a solution. I then measured the distance from flange to flange to help with identification and sent this to Josh. Meanwhile, Dave Harlow from PAE went back to the Xiamen boatyard who checked their records and identified the correct muffler part number (not the one in the manual!) which was checked with Josh who agreed this made sense and he had that particular muffler in stock. Yay!  The second muffler delivery was even faster and arrived on Saturday 14^th November.

Finding assistance

With Gove being a mining town of ~3,200 people, there was  an industrial area just out of town. It did not take long to find a fabrication shop, owned by Danny who had been in Gove for 46 years! One of the guys who worked with him was named Paul, who lived on a catamaran back at the boat club area, so he was the guy who came out to assist. One initial piece of luck before I met Danny was that the section just above the muffler consists of a flange and a short piece of stainless steel exhaust which sits inside a sleeve connecting it to the rest of the exhaust stack. When I was trying to undo one of the nuts I noticed the whole piece moved, so very quickly worked out how it was attached and removed the whole section which I then took into Danny’s where Paul easily removed the old rusted flange along with the old nuts and bolts. Much easier than trying to do insitu.

It did highlight another issue in that the grub screw locking the upper section to the external stack was also corroded after years in the open air and would need drilling out and re-tapping to sort it. The clamp located just below it which you can see in the photo below also had a crack in it so the whole cover needed to be removed so it could be welded up.

On the plus side both the stainless steel exhaust below and above the muffler were in fairly good shape, so no further work was required there.

The next day Paul came out with his tools and so started a long day of grinding off the old nuts and then working at the flange until we could remove it it. I have to say I was the T.A. and Paul did the majority of the work. A very long ,dirty and hot day but finally success at the end. It then took 3 days to clean up the exhaust enclosure of all the soot, rust and crap to a point I was satisfied. By this stage the majority of the upper deck was also filthy, so much cleaning required. As a side note, Suz had put drop sheets across the top of the engine and taped garbage bags around the bottom of the exhaust access to catch all rust and debris falling down.

The new mufflers do not come with the mounting bracket attached as each boat would be different, so the first job was to temporarily fit the new muffler and mark up where the bracket fitted. Rather than risk mucking up the gaskets I used the washers provided with the muffler as spacers as they were the same thickness as the gasket. Once marked up, the muffler and bracket were then taken into town and welded up.  From there it was a relatively simple job to take them back to the boat and fit the muffler and exhaust back together. The whole job from marking up the bracket, taking it into town for welding, then fitting back on Opal Lady took 4 hours.

The Insulation

I had been given the name of a company in Darwin that was reccommended for supplying  marine exhaust insulation. Our friends from Darwin, Michael and Danni, who were with us at Gove on their sailing vessel Natsumi were about to leave for Darwin, so all the old insulation was  sent back with them. I then contacted the company, Bintang Insulation, but unfortunately they were on leave until early November; at that stage the first muffler was still on its way. This was not good timing for us as we wanted to be on the move by mid November, as Australia is experiencing a La Nina cycle and the cyclone season was expected to start early this year.  We wanted to be in a cyclone rated marina in Cairns Queensland by mid December at the latest if possible.

The back up plan was to order thermal insulation from a company called “RS components”, based in Sydney. This came in 2400mm x 610mm x 38mm blankets which could be cut to size and stitched up around the new muffler and flanges. It wouldn’t be pretty, but it would do the job. This then would give us the option of having the insulation made up in Darwin and sent on to our next major stop at Cairns in Queensland, if the timing was not going to work before we left. This insulation backup was ordered 9^th October but did not arrive at Gove until 2^nd November. We found that parcel freight within Australia can be very slow, with international orders sometimes being far quicker. In the meantime, Bintang insulation had arrived back at work and now having a further delay waiting for the second muffler , they were given the go-ahead to make up the new insulation. This also arrived in Gove on 2^nd  November.

Exhaust Air Flexible Sleeve

Similar to the backup insulation, a replacement flexible sleeve was ordered from ebay on the 8^th October and finally arrived at Gove on the 28^th October.  Unfortunately it was not quite as flexible as we needed for the relatively tight curve. We did have some high temperature silicon tubing in storage in Perth, Western Australia; it was left over from when we upgraded the connection from the fan to the exhaust system in the engine room some time ago. Again, as we had the further delay, our younger son Taylor, was tasked with digging this out and air-freighting it up to us at Gove. This arrived on the 12^th  November and was fitted. Solved!

Conclusion and Learnings

There were a couple of key learnings from this whole exercise. Firstly, don’t ignore signs your vessel is giving you. In retrospect I should have followed up on the flakes of rust and pulled off the insulation to have a more detailed look rather than assuming it was all ok. It certainly would have been easier to do this job in Darwin and not exposed ourselves to the problem we had when the muffler failed.

The second learning is to double check what is being ordered, especially if it is an unusual part.  Don’t assume that the manual is correct, which is what both Justin and I did. When you are in a remote location this can cause big delays.

My recommendation to other owners would be to inspect their mufflers after 5 years and then perhaps on a 2 yearly basis to eliminate having a “learning experience” as we did.

In the end we learnt a lot from this incident, got to know Nhulunbuy very well (which is a nice little place with great people) and also got to practice patience while we waited for things to arrive.

After finishing the install we had a 3 day wait for a weather window suitable  to cross the 350 NM wide Gulf of Carpentaria and then it was off to Cape York at the top of Queensland, with the new muffler burbling away happily.