Apologies for the rather long initial post - but this model has something of a story behind it! A couple of years ago I found an old model of Cutty Sark in a junk/antique shop (in Chesham; it's now closed, sadly), priced at £10 due to damage (broken masts/rigging). It was a kit-built wooden model, quite a bit larger than the Revell 1/96 plastic kit, and on initial impressions it looked quite accurate and well made. Never being able to resist a bargain, I bought it! Later, after checking through catalogues, I found that the model was built from the Billing Boats kit and was 1/75 scale. Intact, it measures about 110cm long and 67cm high.
The model looks to be quite old - probably built in the 1970s or early '80s. It was glued together with some sort of slightly rubbery adhesive (probably why the upper masts collapsed) and parts such as the hull bulkheads appear to have been sawn out by hand along printed guidelines, rather than die-cut - characteristic of early Billings kits.
On closer inspection, the damage to the masts + rigging was superficial and easily repaired, but the model's overall level of detail and standard of construction was rather poor - deckhouses, for example, are made from printed pieces of wood, and the bulwarks were devoid of external or internal detail (not even the scupper hatches were represented). A number of parts, such as the figurehead and stern decoration, were also missing. Overall, rebuilding the model to a level of detail which does justice to its large scale + size would be many months of work! As I already had the very finely detailed Revell 1/96 scale Cutty Sark plastic kit to build, I didn't really have much enthusiasm for a project like this - so I carefully dismantled the masts + rigging and stored the model away in the attic.
(I suspect that the currently available Billings kit has been improved in detail and materials quality compared to my 30 year old model. I'd certainly hope so given the kit's £250+ price tag! One definite good point about the Billings Cutty Sark is that it is basically accurate, unlike the Mantua and Constructo kits)
Ever since I bought the model I've had the idea that it would potentially make an amazing radio-controlled model. However, building a working model of a three-masted, square-rigged ship would be a mind-bogglingly complex job, and until relatively recently I didn't even know the basics of R/C boat modelling! Later I wondered about installing a low-powered electric motor, with the masts and sails being static - but the shape of the hull and rudder would make this virtually impossible without radically reshaping the hull. A few weeks ago, though, I had an idea for a possible solution. Why not use a twin-prop drive and steering system, the sort found in many RTR boats? This would avoid having to somehow fit a prop behind the rudder. As I had a RTR receiver unit in my spares box with reasonably good range and reliability - from a RNLI Severn lifeboat - and a pair of new motors compatible with it, I couldn't resist trying out my theory to see if it worked - if not, I could always patch up the hull and (eventually) build it as a static model. As it turned out, the model runs much better than I expected it would. (At this point I ought to give thanks to "Tester" and Martin (forum/site admin) for helping me out with some of the radio components used in this project!)
A few months ago I'd have never contemplated a project like this, but re-fitting the motors and prop shafts in my USCG patrol boat has given me more experience + confidence in installing R/C gear - in particular, installing and aligning motor mounts and prop shafts. The model runs at a reasonable scale speed in the water - thanks to the smaller props and reduced battery voltage - and coasts for quite a distance once the motor is stopped, so no need for constant motor noise when running. It's not too manoueverable when underway (much like a real sailing ship), with a turning circle of several metres, but the twin-motor steering allows it to be reversed or turned on the spot easily if there's any danger of running into weeds, other boats, etc. The operating range is also fairly good (tested by putting the model in the water at the shoreline, then walking away from it and running the motor intermittently; safer than the other way round!).
Here's what it looked like when I got it down from the attic - minus the masts and some of the loose or fragile fittings which I removed for storage.
It looks superficially OK, but close-up it's a bit of a mess, both due to damage + missing parts + some rather poor workmanship in some areas (to be fair to the original builder, there wasn't the comprehensive range of tools, adhesives, materials and reference sources available 30 years ago that there is today). For a 1/75 scale model over 1m long, the level of detail in some areas is also very poor - particularly the deckhouses and bulwarks.
As you can see, the original deck is a single (rather thin) piece of wood with printed plank lines. This has warped and cracked over the years and suffered additional damage when I cut out the access holes in the deck. I'll be replacing it with an individually planked deck (my second attempt at doing this, hopefully it should turn out better than my previous!), using the original deck, straightened out and repaired or replaced in some areas, as a base.
The hull is built from quite lightweight wood - probably obechi or basswood - with some plywood used for the internal structural parts. The whole thing weighs very little, so a lot of ballast will be needed to get it down to the waterline (over 2kg, as it turned out). More helpfully, the wood masts/spars are also very lightweight, which will help a lot with balancing the finished model. Though a lot tougher than balsa, the hull planking wood isn't particularly strong (the hull already had a small dent in it, though easily repairable); but the sealant and copper plating (see later) should give it enough additional strength to protect from accidental damage.
More seriously, the hull was only marginally more watertight than a colander! It had - obviously - been built as a static display model and the original builder hadn't attempted to get the hull planks totally seamless (understandably; I'd do the same when building a static model) but just filled in the gaps with a filler of some sort (it looks like Polyfilla) and sanded it smooth. After about 30 years, this filler (which isn't the sort of thing I'd use to waterproof a working model in the first place) had become crumbly + brittle, and in many places fell out when given a gentle tap. I certainly didn't want to risk this happening when the model was in the water - so I went over the whole hull (after cutting holes in the deck - see below) and removed all of the filler I could find. This left cracks in some places up to 1.5-2mm wide! The worst of these were filled in with scrap wood, then sanded down flush with the hull; the others would be filled in with sealant.
To waterproof the hull, I used Cascamite wood glue. This product dates back to the 1950s or even earlier (though the current formula may well be different) and I wouldn't recommend it nowadays for fine assembly work (I use Evo-Stik waterproof PVA for this), but for sealing and waterproofing a wooden boat hull it's great. (I believe this glue is actually used by builders of full-size wooden boats, so if it's waterproof enough for them it should certainly be good enough for a model!). It's a powder which you mix to a thin paste with water then brush on; after a few hours it sets into a resin-like substance which, after 24 hours, is completely waterproof. I painted the whole hull both inside and out (other than the deck) to give additional structural strength to the wood as well as sealing it. It has very good gap-filling qualities and filled in all the seams between the hull planks.