Installing the radio + running gear was next. This is my first attempt at installing a proper radio system (rather than cheap RTR gear) in a model,
The model is currently powered by a standard 545 motor driving a 40mm prop, with a 12v SLA battery and Viper Marine 15 ESC. The hull already had a hole drilled for the prop shaft, which saved some time and work, but unfortunately the hole was far too large for a standard commercial M4 shaft + tube. After testing with scrap styrene tube to find the right diameter, I widened a M4 tube by soldering a couple of pieces of K&S "telescopic" brass tubing around the tube - it then fitted perfectly.
The prop shaft I had (11") proved to be a bit too small for the design of the model, and in order to get the prop a reasonable distance away from the hull, the other end of the prop shaft ended up quite low down in the hull, which gave me some problems with making an effective motor mount. I tried using a double motor coupling, but this proved too noisy and inefficient; I eventually mounted the motor sideways on a plate bolted between two frames, with a single coupling, which runs quite smoothly and doesn't (as I originally worried) have much effect on weight balance.
The motor is powered by a 12v lead-acid battery, which also provides much of the model's ballast weight (see below)! The prop is currently a 40mm Billing Boats item, plastic with a brass thread; I plan to eventually replace this with a brass one.
I used the original rudder, which was the only piece of hardware included with the model when I bought it! It's quite nicely made from brass and includes a hole for a pin to stop the rudder dropping out of the hull in the event that the tiller arm loosens. However, I did replace the brass rudder tube, as the original one was too short (the top was below the waterline) and not glued in very well, resulting in leaks. The rudder is connected with a standard servo and tiller arm (two rods connected by a brass electrical connector block, to allow the length of the arm to be adjusted). Since taking the above photo, I cut a notch out of the bulkhead to prevent the brass block from catching on it and jamming the rudder.
Being large, constructed of lightweight materials, and with a high freeboard and shallow displacement, I expected this model to be a serious pain to ballast correctly. I was, therefore, very surprised when I put it in the bath (just large enough...) with the cabins, battery and radio gear all in place (no other ballast) and it floated evenly almost exactly at the waterline! It also proved to be extremely stable, not top-heavy at all despite my earlier worries. The model was slightly bow-heavy, so I added about 250g of lead at the stern to correct this.
The fittings and woodwork will add a small amount of topweight to the model, but given how stable it currently is, they shouldn't affect the balance enough to be a problem. (I later removed more of the interior woodwork from the cabins to further reduce the topweight)
I decided to re-surface the hull with wood planking, both for aesthetic and practical reasons. The real boat I'm basing this on has a planked wood hull (as do many older motor yachts) and the plank seams are clearly visible in closeup photos; in 1/18 scale the basic plywood hull just wouldn't look right, even when repainted. And as previously mentioned, the hull's plywood skin appears alarmingly flimsy in some places; I don't know how vulnerable to damage it would be in practice (given that it's been painted with sealant on the outside) but all the same I think it could do with some strengthening!
Planking a hull this large will use a lot of wood which normally might end up being quite expensive, but luckily I had a large stock of 6mm x 1mm strip wood which I bought very cheaply at the Merstham model steam show last year. I've no idea what wood it is (not balsa or basswood). I originally bought it with the intention of using it for static sailing ship models, it proved far too thin and splintery for this, but it should be ideal for adding a surface layer of planking over an existing hull.
A quick test using double-sided tape showed the overall appearance to be fairly good
I glued the planks on with thin superglue (cyanoacrylate/CA) after first sanding down the painted hull surface as much as possible to expose the treated surface underneath. I was unconvinced as to whether superglue would be suitable for gluing wood planks to this surface, but after gluing a few test planks I found that the thin CA produced an extremely strong bond. CA also sets very quickly when gluing untreated wood, so even the curved surfaces at the bow could be glued without much trouble.
Planking in progress:
Once the hull planking was complete, I sanded the whole thing thoroughly using several grades of sandpaper and sanding sticks to give a smooth surface to the rather roughly finished planks. No sealant or paint yet - this will need to wait until I've added the strakes and other structural details to the hull.
Here's the fully planked hull. The planks go a couple of centimetres below the waterline; below this is reinforced from the inside with balsa, and not visible once the model is on the water.
The overall effect is not incredibly neat, and wouldn't be anywhere near good enough for a varnished "natural wood" finish - but once sealed + painted will give a good representation of a planked wood hull. Some of the top planks near the deck have splintered a bit, but will be covered up by the strake which also covers the lower edge of the bulwarks (to be added).