Had a crack with the new sail yesterday, and it has made a huge difference in performance. Kept up with the other yacht on the pond (a 1/4 scale Zephyr racing dinghy which costs around $2000 + completed I think! - $25k for the real one, new) Tacks better now as well,- although typical cat in low wind. Wind was patchy but got an idea of how it will sail in a good breeze.

Changed the winch cord as well, - (used .4mm PF 50lb braided fishing line) as the 1.5 Dyneema started binding on the drum and overtightening the cord, as the diameter changed when fully wound. Much better now,- also added a new closed block with a pivoting leader for the mainsheet as well. The leader was added as the previous Dyneema cord somehow got under the block case on top of the pulley and jambed the winch, even though there was no gap. Hopefully this fixes it.

Probably more small improvements to make, but pretty happy with it at the moment. Very well balanced now, and will sail itself in a straight line hands off. Next test will be to see how it has improved against the IOM (international one meter) yachts.

JB

Yet another mod,- I was at the lake on Tues trying the new centerboards (not much better in the light breeze again, but a slight improvement with 'tacking and backing' ) and got talking to some of the guys sailing IOM yachts. One of them offered me am old IOM sail to play with, which was gratefully received. With a few mods and a new length of 10mm ally tube, the cat now has 95% of an IOM mylar sail and a new 1.73m rotating mast. I made a solid brass strip kicker which grips the mast and boom so as to rotate the mast.

Should be an exciting next test, - hopefully won't need to go swimming ! A masthead float might be a good mod to consider.

JB

The next test in only slightly better wind, had similar results, but the wind was stop start so didn't get enough decent steady wind to judge if the mods had made much improvement. Points very well and sails well, but I decided to go for another mod to change the center of effort some more.
I can't shift the mast back any more, so I thought 'why not move the centerboards forward instead'? I couldn't move the centerboard cases, so I came up with an idea to get round the problem,- bent centerboards. The new boards are a hockey stick shape, which drop into the cases and are pushed forward, then a keeper board is pushed in behind to stop them moving back.
The front edges of the boards locate in between two short 2x2mm rails on the bottom of the hulls to keep them aligned, and stop them flexing side to side. They are kept in place by a couple of aircraft bellcranks. Yet to try this as the weather is rubbish at the moment, but it has to make some difference, as the boards are now 3/4 of their width further forward. We shall see on the next good day.

Meanwhile, here's a shortened vid of the second test not much difference, although it did tack slowly a few times.

JB

Had a chance to give the boat another test run last evening to see if the mods had improved anything. Not a lot of wind, and very shifty, but enough to give it a go. Sailed well enough, but needed more wind to perform. Sailed almost exactly like the original, being hard to tack in a light breeze, needing a bit of speed to track round. In the slight wind increases (hardly gusts) it pointed well and was visibly more responsive.

The sail is not a final version, but was good enough for the test. I'll be giving it more of a go when the wind is better, as I'm sure the performance will improve. I'm quite happy with it so far. Skippers tiller arm action looked quite realistic which was well worth the effort modifying it. Just a shame there was no way to make him change sides, although I used to sail like that in light winds to take weight off the windward hull,- usually lying on the tramp when the wind was steady.

JB

Thought I'd see if I could get a bit of animation into the cat crew. What I was after was a reasonable looking movement of his arm with the tiller extension. The joints were too stiff with the first method I tried ,-(extension sliding through plastic tube glued to his palm) and didn't look good enough, so sent him to the 'boatspital' for some micro surgery.

Shoulder joint and rotation mechanism was cut out using a Weller solder gun with an angled spade tip. The hole was packed with bits of paper towel to build it up for gluing, then 8mm nylon cord was coiled and epoxied into the hole, with the cord exiting the middle. The shoulder ball was cut in half, and the cord cut and epoxied into the remaining slot (ex joint disc) and aligned before the epoxy set.

The elbow was done a similar way, with the joint disc removed from a hole in the upper arm , (was fixed there with an arrow head keeper) then a 6" piece of 4mm macrame cord was pushed up and glued into the hole. The forearm hole was drilled to 5mm and a cross hole drilled into it about 10mm down. The cord end was soaked in cyano glue to stiffen it, and twisted tight till it set, then fed down the hole and picked out of the cross hole with needle nosed pliers.

The forearm was then pulled up the cord until the movement was just flexible enough. I used some Elastoplast tape to support the joints in position while leaving them flexible. Not that pretty but will look the part from a distance. If I get him a long sleeved shirt, you won't know he's been in for major surgery 😉

JB

90% of the painting is done, just the hatch tops to do now. Made a trampoline from glass cloth which was laid on baking paper to stop it sticking, and then had resin rolled onto it. later sprayed with satin black enamel and eyes added to corners. . This is a temporary measure till I can get some shade mesh to make a better one, (I have some mesh coming from Temu)

Have now reassembled the cat and am sorting out a few small jobs in the servo/battery compartment to get things waterproof and fitting better.

Had a crack at sewing a rip stop nylon sail as a bit of an experiment, to see if I could handle my dear old departed mothers 1970s Bernina Read the instructions (Peter🤓) and had a crack. It didn't like sewing through the double sided tape much, or the balsa glue used to hold things in place, but came out reasonably for a first go.

It's only flat so won't work too well, but it's practice (makes perfect right?) I need to try the 'Claudio Gadget' and see if I can't make a mess with that.

Painting is coming along, only the green stripe to do. Time consuming taping/masking one stripe at a time and repeating 3 times, with a days' drying in between each so the tape doesn't rip the paint off.

Bought a crew member for the boat, but he was gender confused and had pronouns,🤔 so had to de-pronoun him and get him back to 'normal' as the boat is pronoun free.
Hopefully have a warm day today to do the last stripe, then the clear then reassembly.

JB

Now the sea trial has been a reasonable success, and the new mods have been done, (not tested but have to be an improvement) it was time to start making it look pretty😀 Major rain and wind (24mph ave with 35mph gusts) the last few days and 20deg C, but today, blazing sun and 28deg C so ideal for painting. Disassembled everything, cleaned up and painted the aluminium beams with an etch primer, then black enamel to finish them. Hulls were primed with an epoxy enamel primer, then a first coat of the sunset yellow epoxy enamel topcoat was applied.

Showed up a lot of minor areas which needed re filling, but that can be done once the first coat is completely dry. It's going to take a few coats to get it all done, but it's looking ok so far. Thick undercoat will fix most of the minor problem areas, or maybe body putty. Colour is almost exactly the same as on the full sized boat which was good. probably take a week to finish the painting, then should be good for another test.

JB

Finally got a chance to give the cat a test, but couldn't find a decent place to try it which was sheltered, as an 18mph wind was on shore and the tide was out. After driving round the local beaches and estuaries, I finally spotted a large tidal pool at one beach which was just deep enough for a test.

Wind was going from around 2 to 20mph in gusts and rotating 180 deg, so not ideal, and the useable water was only about 30ft wide by 80ft long, so not a lot to play with. Cat sailed ok, but the rudder servo was doing odd things (found out it was the servo extender not working with a new but bad digital servo) and getting intermittent rudder of only around 5deg each way. Had fun anyhow running up and down the puddle, and found out what needed changing, which was the point of the test.

I found the mast was too far forward, and it needed a lot more rudder. I have now shifted the mast back 45mm and changed the rudder servo (now without extender). Rudders are good for movement now, as I have changed the cable from the crossbar to a horn on the side of the rudder,- now has about 40deg throw each way. I have also shortened all the servo/battery leads now to make them fit better in the compartments, as there was a bit much spaghetti previously. Boat looks to have reasonable speed and is very light on the water (only weighs 2.6kg) It will be interesting to see what difference a proper sail will make.

I'm disassembling everything at the moment and will be painting it in anticipation of the problems being sorted. Painted the servo bays with acrylic paint to waterproof everything. Reasonably happy with it as a first test, as it's always a gamble designing as you go.

JB

Almost ready to give it a try. Winch, rudders, etc all sorted, just doing a few wiring mods to make things fit better, plus on/off switch and charging point (want to leave it closed up, to save undoing screws every outing) Mainsheet was fun to work out and set up, but a lot of choice words helped get it done 😎

Winch sits in the port hull, servo, RX and 4 cell NiCad square pack sit in the stbd hull. The lead for the winch comes through the aft beam to protect it. Compartment covers have sponge seals, but still some proper waterproofing to be done round the winch and rudder cable . I have to completely disassemble the boat to paint it once it's all finished, and make a proper sail (using the land yacht sail to test it with)

JB