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The day had been perfect, flat seas, good tides and the mackerel had flogged almost anything put in the water. However, back at the boat ramp, our boat Merlin had spewed at least eight litres of seawater out of each drain plug. We had noticed an increasing quantity of water coming out of the bungs and had put it down to water coming in over the side. This time, however, we realised it was something else – she was leaking!

Closer inspection of the twin hulls at home made our hearts sink. We found a couple of pinprick holes in the middle of the hull between the sponsons. Having recently replaced the outboards and the instrumentation, we felt we had already had our quota of boat-owner probs. However, it was obvious we had more work to do.

I drilled out the corrosion holes with a countersink bit to clean up the surrounding metal and towed Merlin back to its builder, Cairns Custom Craft, so that the holes could be welded up or even plated.

Kevin had taken a good look at the problem and shook his head sagely, which I took to mean the job was not going to take the, “twenty minutes while we had a coffee with Marcel,” which is what we’d hoped.

Apparently, the corrosion had taken hold over the years and now it was a bigger problem than we had expected. After 18 years of hard work and great service, Merlin had developed the dreaded alloy cancer and needed more than just minor help. In fact, it needed a major cut and shut underneath.

Harry (Megg) and I were stunned and devastated by this news. There was no way we could afford to have this work done as just lifting up the carpeted deck would take at least two days, let alone the cutting and welding. Couple this with the ever upwardly spiralling rules and regulations which now govern, (read “choke”), the recreational fishing scene and we were seriously considering packing it in.

Marcel suggested that we could remove the flooring ourselves as that was the most labour intensive part of the rebuild and the part no one in the factory wanted to do. Furthermore, in the years since Merlin had been built, Marcel had made several modifications to the design of the hulls and the newer models were better in terms of handling and far easier to push through the water, (i.e. more fuel efficient). These modifications could be made to our hulls since the centre section had to be cut away.

This would have to have been one of the most difficult decisions we have made for a while. A few years ago the decision would have been an easy and enthusiastic yes! But now, we thought twice about whether we wanted to take this project on. However, finally our love of fishing and the great outdoors gave us heart to go ahead with the repairs and modifications.

All of the donkey work like pulling up the floor, cutting new floor panels, re-carpeting, etc., would be done by us so that only the actual metal fabrication and welding would be completed in the factory.

When the boys at Cairns Custom Craft had put the original floor down they did not skimp on sealant and glue that’s for sure. It took Harry and I the entire weekend, starting at 7.00am and finishing late in the evening both days, and half of Monday, to smash, (literally), out the old carpet and plywood decking. Big crowbars, sledge hammers and cold chisels were used and progress was glacial. On Monday afternoon when we backed a gutted Merlin back in to the factory, both of us were sporting bruises on hands, arms and legs. Harry was walking around like the hunchback of Notre Dame and didn’t seem her usual chipper self. Small wonder the job of removing decking is not a popular one in the factory!

The cut and shut:

I visited the factory to take some work in progress photos but it was a week later that we got the phone call to come back and check out the new improved model. The hull had been cut and shut but this time with 4mm plate rather than 3mm (mostly to allow better welding to the older, existing aluminium), the strengthening ribs had been moved to the outside of the hull and, as Kevin put it, “trainer wheels” welded to the outer sides of the two hulls.

Merlin was one of the original Hydro cat designs, built to give a very soft ride in rough water and cut through choppy water, which it certainly did with consummate ease. We often come home at 18-knots while the monohulls have either dropped off plane or are laboriously pounding their way through the swell.

The compromise, however, was that the outboards had to push harder to get the hull on plane. Now, the hulls had been made a little wider at the keel giving the whole vessel more buoyancy therefore making it easier to get the boat up on to the hydrofoils and keep it there. Marcel assured us that this would transform the cat and give even more stability at rest.

Harry mentioned her bad back and asked what the modifications would do to the ride but again, Marcel assured us, the ride would still be soft. The thing that struck me was the relatively small size of the extra buoyancy tanks; it didn’t seem worth the effort.

Having decided at the outset that a new paint job was out of the question, (estimated cost of $4000 or more), we could begin the fit out that afternoon but we decided to go at it a little slower. With the boat out of the water we had decided that rather than glue the plywood to the hull and then glue the carpet to the ply, we would put down rubber strips on the internal frame and then bolt the plywood with carpet glued on to the frame so that if the floor ever needed lifting again it would be possible to do so without wrecking the whole structure.  

On the carpet:

Of course, this meant making up threaded plates and attaching these under the bearers and, as usual, I had totally underestimated how difficult and how long it would take to do this. The other thing I hadn’t concerned myself over was that professional carpet layers make sure the carpet all goes in one direction, i.e. the grain of the carpet runs left to right or forward and back.

Our method of laying out the carpet was to purchase the minimum length of carpet possible and then lay the plywood sections on top of it like a giant jig saw puzzle. The end result of this is that the carpet looks a bit strange at first because it appears to have light and dark patches, however, since this was an “el cheapo” job I didn’t care as much as the pros would. It still looks heaps better than the sand sprinkled on varnish job we had toyed with in the planning stages. One thing Harry did insist on was putting several coats of marine sealer on the plywood after all the holes were cut to prolong the life of the plywood as far as possible.

Another surprise here folks, plywood isn’t all the same quality. When searching for a rock bottom deal on plywood sheets I had a look at some imported sheets on a stack in the timber yard, what a joke! The stack had about 15 sheets of plywood in it and yet the whole stack had warped. Apparently, the timber used overseas isn’t really suitable for use as plywood at all, and the story goes that some sheets are so bad they actually bind on a table saw when cut. Advice from a professional shipwright was sought and he described his one and only attempt at using this cheap imported plywood on a trawler with absolutely disastrous results. Not only did the ply warp, it also warped enough to delaminate itself and pull screws out of surrounding timberwork.

Whatever you do, don’t get shipwrights started on imported plywood, you’ll be listening for a couple of hours. In the middle of the first sermon, one of his cabinet maker mates joined in on the conversation and insisted I have a look at a box he had made out of the stuff, enough said. Back to good old Aussie C.C. grade ply. Even at nearly double the price I could justify the expense to anyone thinking of doing the same sort of work on their boat after seeing the evidence.

My brilliant idea of making the deck removable began to lose some of its gloss once we realised that in order to make all the threaded holes in the frame line up exactly with the holes in the plywood, the deck would need to be very carefully marked, drilled and then the plywood refitted to check the alignment a couple of times before we could even think about gluing the carpet on. This meant countless trips up and down the ladder at the stern of the boat, wriggling tightly fitting sheets of ply into place, finding they didn’t match exactly, discussing who had measured incorrectly, discovering it was my fault again and then hauling it all back out into the workshop.

What a drama. Harrys’ earlier impersonation of the Hunchback of Notre Dame paled to insignificance now and we both felt we looked like those knuckle dragging Neanderthals you see in biology textbooks.  

Playing with plywood:

We had learned some valuable lessons about gluing carpet to plywood with that incredible high strength yellow contact glue while fitting out the barra punt, (see previous issue of TBF). Tragically, however, our cat had somehow missed out on this education and jumped onto a sheet of ply with yellow glue just at the tack-off point. Luckily, I am an alert sort of chap and noticed the very pissed-off cat struggling with the glue before the carpet went on top. Another disaster narrowly averted. Cats and boatbuilding do not seem to go together terribly well it would seem.

Throughout the rebuild Megg and I were re-evaluating the wisdom of doing this in the first place. I know the boys rebuilding a Bertram 28 have similar difficulty motivating themselves once the motors were rebuilt and the boat was a floating, going concern. We have all spent some time at the boat ramp and although you regularly see a selection of new outfits, new outboards on old boats seem a rarity. Makes you wonder what happens to all those old hulls and outboard motors doesn’t it.

The point is we were really having second thoughts about whether the cost and effort was going to be worth all the heartache. Would we be better off the outfit “as where is” package? We tossed that idea around quite a bit but in the end decided it was still worth having our own boat, rather than going down the charter boat route.

The bottom line though is that once you commit to a big project like this you lose money big time if you do not complete it. So you need to stay motivated and stick to the program.

The verdict was good:

Finally, we got her finished and after some delays due to adverse southerlies we managed to get back afloat. While the appearance may not be brilliant, the transformation to Merlin’s performance and handling has been breathtaking.

Give it full throttle from idle and the cat seems to leap up onto the plane like it had a stick of dynamite under its stern and, amazingly, at the same revs as before, (and with exactly the same motors of course).

The boat is now going a good three to five knots faster than before. She now tops out at an impressive 35-knots, way more than what she did before.

After a few offshore trips we now know the small modification to the hulls have made a huge difference to both the stability and performance of the craft. By altering the shape of the hulls by a matter of 10cm, Marcel has transformed the old boat into a whole new outfit – which shows what modern computer-aided design coupled with experience can achieve.

So was it worth the effort? In our case it probably was (we are still wondering about this) but mainly because we did most of the work ourselves, and had the benefits of an understanding boat builder, it worked. If we had to pay someone to do all of the work I doubt the exercise.