I had never serviced the three air valves on my old 10’ foot Caribe RIB dinghy since I bought it used. It stayed suspended on davits on the stern of my schooner Britannia, for months at a time.
I’m a believer, (most of the time anyway), in the old adage, “If it ain’t broke, don’t fix it.” But as with most old dinghies, it was necessary to re-inflate it from time to time, when it went down a bit. Just lately though, I had noticed the bow section needing more air than the other chambers, so it was time to find out why.
The most obvious thing to look at first were the inflation/deflation valves. There are three separate chambers in my dinghy, each served by a valve, called a Halkey Roberts air valve. (www.halkeyroberts.com). These type of valves are also very common on other makes of dinghies.
I used the age-old soapy water testing method to find out if the valves leaked, mixing a splash of washing-up liquid in an old spray bottle, and spraying the valves. There they were, tiny bubbles emerging from round the outer ring of the bow chamber valve, indicating the certainty of a leak. Surprisingly, no air was escaping from the inside of the valve itself.
Unfortunately this meant the valve had to be removed, to be at least cleaned, or more than likely replaced. I hadn't a clue how to do this, so I paid a visit to my local dinghy/liferaft repair shop, to pick their brains. On seeing a new complete valve it was obvious how the thing worked. It consists of a threaded holder inside the actual dinghy chamber, and the outer valve, which screws tightly into the holder. An airtight seal is formed by tightening the two together and trapping the dinghy material between them. There is also a cap which locks on top of the valve, to keep water and debris out of the inside. It was explained to me that I needed a special removal wrench to unscrew the two valve halves, which would be very tight, but this could easily be made from a short piece of ¾” plastic irrigation tube.
I came away with a new valve, and made my own removal tool in five minutes in my garage, by cutting a slot in one end of the tube and a hole in the other end to carry a screwdriver.The cut-outs engage in the inside of the valve, which indeed proved to be very tightly screwed together. I needed the long screwdriver to loosen the two halves. This is a normal right-handed thread and best started with the tube fully inflated, when it is more rigid, but once the valve came loose I found it could be unscrewed by hand—but this is where it got tricky...
The holder inside the dinghy is not physically attached to the inside of the tube, so before the valve is unscrewed completely it is necessary to hold the inner half with one hand round the boat material, to stop it falling inside the tube. Once the valve was removed I put a screwdriver through the holder to stop it disappearing into the tube—or so I thought. By the way, the inner valve holder cannot be pulled through the hole in the tube either. The hole is much too small and the holders must have therefore been installed when the dinghy was built. This made me wonder why I needed to buy the inner holder at all, but that’s how they are sold.
On close inspection of the circular flange of the valve is was obvious why it leaked. It was extremely dirty, with bits of grit most of the way round the seal. The circumference of the hole in the Hyparlon tube material was also dirty. I used Zylene liquid to remove all the ingrained dirt from the valve.
The circumference of the hole in the tube was more difficult to clean. The screwdriver need to be removed and the loose holder held in place with one hand to stop it dropping into the tube, but naturally, the inevitable happened. The holder slipped out of my fingers and vanished inside the dark tube. After a lot of fiddling around I managed to feel where it had fallen and waggle it back up to the hole, then line it up to re-insert the new valve. It certainly would make things easier if dinghy makers employing these type of valves, could somehow attach the inner holder to the tube. However, I was told, under no circumstances to be tempted to use any sealant on either of the valve flanges. They need to be screwed together dry.
Once I managed to get them level, screwing the two together was quite easy and I wound the new valve right into the holder until it was finger tight. I then fully inflated the chamber using a small but powerful battery powered compressor. I then tightened the two halves together as hard as I could, with my home made wrench and screwdriver.
A water test proved I had solved the valve leak on the bow chamber, and apart from loosing the inner holder it had all been fairly effortless. I therefore decided to ignore my old adage “if it ain’t broke…” and take the other two valves apart, for inspection and cleaning. Indeed, they were both just as dirty, not only on the outer sealing ring, but also two internal rubber O rings. One is on the valve stem forming the actual air seal and the other on the cap, Both can be easily prized off and cleaned. On re-assembly I even managed to not let the inner holder fall into the tube again. These two valves should now be as efficient as the new one.
This was all quite a satisfying new maintenance/repair exercise, and I am now a little bit more knowledgeable about another part of my boat.