Kitshack 28" Vosper 68' RTTL

Started by neilw

10 updates 88 likes 19 comments
neilw Opening post 2

Kitshack 28" Vosper 68' RTTL

I was going to put this on the project shelf and look at it later in the year, but it has proven difficult not to pick it up, plot and scheme so it looks like this one will join the Eventide and Crash Tender on the bench.

I found this advertised on a Facebook group for sale as a project and liked the look of it and thought the waterjet might be something different to play with.

Also there is a bit of a family connection as my father served in RAF Gan where the sister ship 2748 was based, so at one point was thinking this one would be model of 2748 in the white tropical paint scheme.

The hull has been built well, and most of the superstructure is complete, there’s a box full of bits and pieces so I think everything is there to finish the boat, if not I have now have a load of timber in stock left over from other projects.

Turns out that the original RTTL 2748 has been restored, though currently has no interior and is about 4 miles away from me. She was also based at RAF Mount Batten (not far from where is is currently in Plymouth) in the 1950s, so a both local and family connection

As the Kitshack 28" RTTL was very similar, if not identical to the Veron kit so I made contact with Phil Smith's son who has the archive of the Phil Smith designs including the boats he produced for Veron. I now have the full set of plans, templates and build instructions.

So, the plan is to now build the model to be 2748 from the mid 1950s before the addition of the centre roof, as she would have been when towing targets from Plymouth.

Many thanks to those responding to my thread on the forum about the boat, particularly to RichardH and dave976 for letting me have lots of information on RTTLs. Having spent the last few days immersed in the research phase I can't wait to get started. The first job has to be to remove the waterjet and make good the hull so I can fit the propshaft, rudder and keel.
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neilw #2 of 11 2

Getting rid of the waterjet

The boat came with a waterjet fitted to a brushed motor. The intake of the water jet was recessed into the hull and sat on a large pad of polyester filler.

As I’ve decided to fit a brushless motor, prop shaft and rudder I needed to make good the holes caused by the water jet. The filler took a while to remove, I have a dislike for polyester filler, it absorbs water, pinpricks easily, is heavy, brittle and provides little structural support.

To fit the waterjet the last 150mm of the keel had been removed and also noticed the transom skin had come away from the rest of the structure, caused by the cutting of the hole for the outlet nozzle.

With part of the keel missing the polyester had spread under the balsa floor, filling the gap between the balsa and outer skin. I made the decision to remove the balsa, it had broken up in many places so out it came. The polyester filler hadn’t adhered to the hull skin.

With all the filler and balsa removed I scarfed in a new keel using 3 pieces of Obeche and epoxied them in place. Hole in the bottom was squared off and a piece of 2mm ply epoxied in place. The nozzle hole was also neatened up and piece of 0.8mm ply epoxied to the end of the keel. I’d already fitted a new inner transom piece from the same ply.

Decided not to replace the balsa in the bottom of the hull and fitted a panel of 0.8 mm ply epoxied to the keel and fixed in place with an epoxy fillet.

Although there’s some heavier duty timber on the keel, needed as I’ll be drilling holes for the prop shaft and rudder, the back end of the boat is considerably lighter with the polyester filler removed. The epoxy and used for gluing, fillets and fairing weighed in at 10 grams as also used to fair the bow, some will removed with later sanding and tidying up.
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neilw #3 of 11 2

Kitshack 28" Vosper 68' RTTL

Seem to have found some time to work on the RTTL.

Decided to tackle the fiddly bits first - the chine rails, gunwhale and toe rail. The gunwhale was required as the previous builder hadn't adhered to the instructions of leaving 1/8" of the deck to overlap the hull.

At this point I decided to go off plan and work on a better method of fixing the two cabin sections in place. The plans suggest using 12 pieces of dowel as deck latches, representing air vents. The two sections sit on a recessed lip on the main deck.

Having been fortunate to receive a number of photos on 2748 from the daughter of the person who bought the boat in the early 1970s I've been able to see that the original boat didn't have this many vents. I think it detracts from the model to have so much unnecessary detail so will be fitting the 3 each side that the original boat had fitted. These can now go in the correct place rather than be used as deck latches.

I realised that the rear deckhouse section (with the towing cabin) could be adapted to hook under the rear deck and be held in place with two turnbuckles locking under the deck beam. This can be fitted with front section removed. Fitting the front section uses the same approach, it hooks under the foredeck and the rear section uses to turnbuckles to lock under the side deck. In order to gain access to the front section turnbuckles I adapted the engine room hatch (behind the main cabin) to be removable.

With the two cabin sections now able to be held firmly in place I needed to look at the aesthetics of the cabins in the deck recess. The previous builder had done a decent job in cutting out the deck parts, but there was a gap between the edges of the cabin sections and the deck, this gap ranged between 0.5mm and 2mm. I wanted to minimise the gap and have a tighter fit between the cabin sections and deck so the cabin sections were wrapped in clingfilm (to prevent any filler adhering to them)and fitted in place using the hooks and turnbuckles.

With the wrapped cabin sections in place I worked some ultra fine filler in the gaps. Once this had cured the clingfilm wrapped cabin sections were removed and the filler sanded back to the deck, leaving an infill that now provides a neat and snug fit for the cabin sections.

The window frames have been fitted, they still need a bit of fettling and the cabin roof now has the various roof strips added to it and the cockpit been lined and edged. I'll need to finish the sanding and fairing of the window frames and get them painted before fitting the windows. Once the windows are fitted the cabin roof can be fitted and faired in to the rest of the cabin top.

It is looking a little rough at this stage, the boat has now received the first coat of primer to find the lumps, bumps, open grain and dings that need attention.
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  1. mturpin013Bronze
    Admiral
    Some interesting detail, its coming along nicely, keep at it and keeping us informed of the detailed processes, we can all learn from a well detailed blog.
    Liked by neilw

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neilw #4 of 11 2

Pylon mast and getting some paint on

It has been a while since updating this blog as I've been spending a lot of time building the Pylon mast and have 6 attempts to get the birdcage antenna.

The plans suggest using wood and brass to make the mast, I went down the carbon route for most of it as carbon rod is now very cheap, the whole thing cost me less than £5, excluding the brass I wasted in trying to make the birdcage.

The main structure is 3mm carbon rod with 1mm and 0.8mm carbon for the yogi aerial. I’m using a slightly different RADAR as I want it to rotate so the RADAR shaft will replace the loud hailer shaft.

The di-pole ‘birdcage’ took me six attempts, having tried carbon and brass, couldn’t get it right as is 50mm long, 9mm diameter. Finally found some 1mm plastic with a metal core that bends easily and glues together.

Some of the photos show a triangular plywood web on the platform and the upper support for the yogi aerial (as in the plans), I removed this after the main structure was built as the carbon didn't need this support.

The Pylon mast is nearly finished, just needs the nav lights added, went to fit them today and it looks like I forgot to order the anchor light.

The other part of the boat that has taken ages to get right is the RAF Roundel on the main cabin roof. This is painted over the ten strips on the roof, making masking up of the concentric circles very difficult to get right and to stop paint flowing under the making tape. I realised I should have painted the roundel before adding the roof strips.

I ended up buying an adhesive RAF decal of the right diameter, sticking it in the right place on top of the roof strips and then using a scalpel to cut the pieces that drop into the valley between the strips. The sides of the strips were then painted in an appropriate colour to blend it all in, thanks to my lovely wife with a steady hand a very small brush.

The rest of boat has undergone several cycles of paint, flatten back and repaint. The hull now has several new holes and fittings. The photos I have of 2748 in Plymouth show 4 ports on the transom, judicious measuring of the photo has allowed these to be fitted to the model, along with a stern ladder. I managed to track down some reasonably priced portholes, so the hull now has 7 holes each side to take these later.

The major components are now built, hull, main superstructure, towing cabin deck and hatches now only need some light sanding and then the final coats of paint can go on before the fun part begins - sorting out all the fittings and details.
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4 comments
  1. neilw
    Lieutenant Commander
    Hi flaxbybuck

    It is surprisingly robust, I’ve managed to drop it 3 times and only had to do one repair! Just need to avoid the overhanging trees and bushes at my boat club lake.

    If it does go horribly wrong I’ll treat it as an opportunity for a Mk 2 version.
  2. mturpin013Bronze
    Admiral
    I had similar issues with parts for a friends aircraft carrier, I used 1mm and 0.5 mm brass wire and soft soldered the framework together, I may have a go with carbon fibre as I know he want some more making.
    PS the centre mast is only a "prop" for manufacture
    Liked by DaveWhittaker and stevedownunder and

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neilw #5 of 11 2

Getting some painting done

Managed to work towards the final coats on the RTTL, also did some on the Crash Tender.

Got the final coat on the bottom and decided to have a white day, painting the white roofs of both the cabins. Hopefully will just need one more coat.

Flattened the grey of the superstructure ready for the top coats once I’ve finished the white.
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  1. RodC
    Lieutenant Commander
    I'm impressed by your birdcage antenna & your 2 Yagi-Uda's. My final career was Radio Inspector.
    Liked by Colin H and neilw

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neilw #6 of 11 2

Very fiddly portholes

I’ve left the two black boats a couple of days for the hull paint to harden off. So today was the day for a job I really wasn’t looking forward to but needed doing before the hull is masked up while I finish the the deck paint.

The RTTL has 7 portholes each side running in a line from mid ships towards the bow. The plans say to paint the portholes but I found a supply of reasonable priced brass ones so bought a load to do the job.

I drilled the holes in the hull a while back so needed to fit the portholes. These are brass that I painted black. Outside diameter is 8mm, the holes in the hull are 6.75mm and the plastic ‘glass’ insert is 5mm diameter.

The tricky part was fitting the plastic inserts, luckily there were extra inserts included so after bending a couple while trying to fit them I found an old paint bush handle was the correct size to act as a plunger to push the inserts firmly into place.

Obviously I’d painted the hull after drilling the holes so these needed carefully reaming out as the paint made the holes slightly smaller.

Some CA was decanted and applied to the inside of the holes in the hull and the portholes all slotted into place.

Quite relived now that job is done.
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neilw #7 of 11 2

Back to painting.

Well, not done much in the last month as went on holiday and have been sorting some of my other boats so I’ve got a few to use while the projects progress. I ended up taking the motor and ESC from the RTTL for the unknown varnished hull so has to source a new motor and mount to replace it. All fitted now.

Finally got some time on the RTTL, just wet sanded all the grey back ready for the last coat (hopefully). Fitted the deck sections place and did some fettling to get the two sections to fit and lock in place. Even got the mast out to see what it looks like put together. It is finally looking like a boat.
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  1. neilw
    Lieutenant Commander
    The paint is Hempel Multicoat with about 15% thinners, the grey and black are semi-gloss so not too shiny.
    Liked by Colin H and chugalone100

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neilw #8 of 11 2

And now some detailing

Well, I’ve declared the main painting done, have a couple of areas needing some fettling but I’m pressing on with the detail.

Finally got the Trimline to work, went for a narrower line and it looks like it has adhered. The numbers went on without too much swearing, though I’m glad I ordered sheets of different sizes as the original large ones (45mm) look fine on the transom but were too big for the hull. The 40mm ones fitted in nicely between the portholes and match the photos of the boat I have when she was based in Plymouth.

Have most of the deck fittings fitted, just need to add the deck cranes and scramble nets before finishing off the main cabin section.

The rear deck section is now complete apart from a little bit of paint touch-up, has cabin windows and a rear “canvas” cover for the target towing cockpit. Quite pleased with the “canvas” cover, cut from an old sheet I used for painting and decorating so has visible warp and weft. Mixed up a variety of Tamiya paints to get the muddy green/grey/brown canvas used by the RAF.
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neilw #9 of 11 2

The end is in sight

Been wiped out with a summer cold for the last week or so meaning work has slowed a bit.

I have managed to get the last fittings in place and have a few small areas of paint to attend to, but I have done the first fix of all the running gear, it all works fine so needs a tidy up at some point.

I was hoping the recent water pumps I bought from China would be quieter than the others I have but these turned out to be quiet but with a very reduced flow rate so I’ve fitted one of the noisier ones until I can find an alternative.

I did get the boat into a test tank - a wheelbarrow full of rain water and she sits nicely on the waterline even with a 5000 mAh 2s LiPo at the front end. Will have to see if this is too heavy when on the water.

I’m hoping to run her at the lake on Friday, albeit with a few cosmetic bits still left to do.
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  1. flaxbybuck
    Captain
    I have enjoyed watching your build Neil, and looking forward to seeing 2748 on the water. Good luck😉
    Liked by neilw

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neilw #10 of 11 2

Close, but no cigar

Had hoped to post a video of the RTTL on the high seas. It did get afloat, albeit too briefly as the propellor fell off after a few minutes, how I laughed. Of course I hadn’t tightened the lock nut. Lesson learned, might even use some thread lock next time.

Did notice the trim is wrong as she is down slightly at the bow so will be reversing the set up so the battery will be towards the stern and the lighter water pump towards the bow, so replumbing will be required before the next trip out.
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3 comments
  1. neilw
    Lieutenant Commander
    Thanks Bill. It was completely my fault, in the rush to get it on the water I’d forgotten to sort the lock nut. Won’t do that again.

    Another school day!
    Liked by chugalone100 and Scratchbuilder

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