Lumba Lumba Restoration

By Cargoman 28 entries 12 Nov 2020 — 9 Jun 2021
180Likes
52Comments
Chapter 01 / 28

28 chapters · Page 1 of 3

Cargoman Opening post 1

Lumba Lumba Restoration

Got the idea for this boat after seeing a friends one in America, I found out later that not only is it a discontinued kit but getting hold of a second hand one aint easy.
So after seeing one on E Bay I bid and won, the boat has been part started and then left for what seems many years as there is damage to parts and some bits missing.
The hull has been really well built as can be seen on the photos but someone else must have had a try at it as there was balsa stuck over the windows with portholes stuck in. As for the running gear I have decided on twin screw so the single shaft has been removed and 2 new shafts ordered.
Liked by ChrisR and Gillman and

Part 1

The main deck was built but the cabin had seen better days so I drew out the shapes and binned the cabin bits with a veiw to constructing it from plasticard a lot further down the line.
I have started to add some parts that were missing namely the bridge deck front which I have used some obechi sheet.
Although the hull is well built it is balsa and by the water that came in when I tested it very old dry balsa so Im fibre glassing it inside and out and hopeing that I can then get some primer on.
Liked by Gillman and Colin H and

Part 1 Con,t

Well after a lot of hours I have finally got the hull sealed and all the broken bits fixed and filled,the bow was smashed at deck level and there were numerous holes in the foredeck. The upper deck and the foredeck needed sealing so out with the sanding sealer, funny thing I got quite a large tin on the day before lockdown and you guessed its gone. The outer hull got 2 coats of fibreglass resin and the inside 1 coats followed by flatting off filling and flatting again. I then blasted bits of primer on to see the faults and filled again meaning it now looks like a patchwork quilt but it sealed and smooth. Two main features stood out to me with this boat and those are the oblong windows and the small after deck, so these have to be neat the windows had been covered over with balsa glued on with evo stick and portholes put in. After removing this I was left with not only damaged but uneven sizes of windows now much improved I hope.
Ordered the new shafts just waiting for delivery so I think I might start with installing these next.
Liked by ChrisR and Colin H and

Balsa deck

The upper deck is as the rest of the boat is balsa and I sealed it with three coats of sanding sealer and then after sanding filled any imperfections with model filler. Then comes the time to mark out where the cabin sits etc so with a pencil and ruler I start only to find that what I thought was a solid surface was similar to writing on custard. This deck must have been a soft piece of balsa sheet and also my misjudgment of how much work it takes to seal balsa. Next step fibreglass tissue and resin stippled on with a finishing skim with filler and bingo its a firm surface at last.
Liked by ChrisR and Colin H and

Part 2 Running Gear

The new 13 inch shafts arrived and I have prepared a pair of 7 inch tubes with oilers fitted, also I made from brass and some bearings from a shaft the outer shaft supports. To set up the shafts in the boat I made 2 shaft aligners made from brass tube to keep everything in line before fibre glassing the parts in.
The choice of motors was based on an article I found on the web who had used a pair of MACK products motors in the states and their website showed they were quite tame so I already had a pair of 540 size motors of unknown pedigree but a pair never the less and not too quick or ampy on 6 volts.
The problem was to make a decision as to the angle to fit the shafts too steep and they look awkward too shallow and they are too low below the waterline, so a compromise was found and although the angle is a little steep they will be fitted at that.
Liked by ChrisR and Colin H and

Running Gear Cont,

Solved the problem of the shafts being at a steep angle (me,) poor maths and even worse drawings so I extended the tube length by and inch which reduced the angle and Im more happy with the look now. The tubes have been fitted and set up with the aligning tubes I made from brass, following that I fitted the couplings and test fitted the motors. Next will be the final fit and test run followed by rudders.
While all this is going on I continue to work on getting the hull into primer being made of balsa it has suffered a string of bangs and bumps and having to seal a lot of the balsa the job goes on and on but its getting there.
Liked by ChrisR and Colin H and

Running Gear Cont,

The outer shaft supports had to be remade as the originals were made from too thin brass which flexed a little so upgraded supports with phosphor bronze bearings have been made and fitted now.
Liked by ChrisR and Colin H and

Rudders

Built a couple of scale type rudders as there are no actual photos of the real ones its a bit of a guessing game. Made from a piece of brass tube soldered to a piece of brass sheet and then clad with 1/16 ply on each side glued and clamped, photo shows just a few clamps. I then sand them to shape and coat in resin followed by more sanding and then a coat of primer.
Liked by Colin H and MouldBuilder and

Running Gear

Couple of photos which show how I received the boat with a single shaft rudder and prop and now with twin shafts etc fitted. A little more to scale but in truth I believe the kit plans do show an alternative twin shaft fitment.
Liked by Colin H and MouldBuilder and

Prop size

Time to decide on prop size as I already own a 3 blade 35mm brass prop I lashed out on a matching one. The decision based on the fact that running on 540 straight drive motors I did not want to over do the amps or heat.
With the ever rising cost of brass props I hope Im right.
Liked by MouldBuilder and Ianh and

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