Robbe PT15

Started by Cashrc

16 updates 94 likes 64 comments
Cashrc Opening post

Robbe PT15

Hi y’all. Did a little trading with my buddy Larry Buchwalter a few months back, came home with a just started Robbe Paula III and a NIB Robbe PT15. I don’t have a military boat in my fleet, and, since I’ve wanted one of these kits for quite a while now I decided to start building on her last week.
I’ve made a few changes, laid the rudder servo on its side instead of standing up. To me it’s more secure that way. I had to make up a servo mount from scrap balsa and ply. However, where it mounted made it difficult to install or remove the servo arm as the hatch edge of the deck would be in the way. I mounted the servo with Allen head servo screws, and an Allen head screw retains the arm. I also enlarged the aft hatch, which gives me room to service the servo if needed. I also cut downs the stock battery tray to save room, and mounted it off just off center. I’ll either be using a 6 cell pack or 2 cell LIPO for power.
Speaking of power, this kit came with both the fittings kit and a Robbe navy geared drive. I’ve decided to use the gearbox, shaft and prop, but I’m ditching the EF76 motor for a silver can Mabuchi 540, my resining being that the stock motor has a lot of torque, but might fall on its face on 6 cells (the plans originally called for an 8 cell 9.6 volt pack). I think the 540 will do fine, but I might try to dig up a Graupner Speed 600 and use that. I’m still open on power.
Anyway, the hull is built, gearbox and rudder servo installed, rudder linkage and rudders mounted. This boat will challenge my skills, as it’s not quite as easy to build as some of the other Robbe kits I’ve built. There’s lots of details, but fitting the deck to the hull in this boat was...well, it was a job. It looks okay, everything is straight, but I do need to do some filling and sanding to make it really right.
I have pics of what I’ve done so far, any questions or comments fire away!
Cash
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6 comments
  1. MouldBuilder
    Admiral
    I use the Stabilit Express for most of the joints that need good strength and to be totally water tight. It is a really reliable glue. It is quite difficult to get in the UK also. I get mine from Germany.
    Peter.😊
    Liked by BOATSHED and Martin555

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More hull work

Nothing exciting this go-around. I added the rub strips to the hull, and the aft platform. I found that I inadvertently used the 3mm rub strip material for the inner deck supports!!! And, what makes this worse, is that I measured the abs beforehand, and I sweater it looked 4mm on the ruler, which is the size called for to reinforce the hull/deck joint. Sooooo....I used some 1/8th spruce and hard balsa stripwood with the remnants of the 3mm abs that I had left, and it turned out fine. I also applied a little Tamiya filler at the hull/deck joint and gave that a good sanding when dry. I’ll give the upper hull and deck a light coat of primer possibly tomorrow, that will help show any blemishes that need to be addressed before the hull is painted.
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3 comments
  1. Martin555
    Fleet Admiral
    Very nice indeed Cash.
    You are doing a brilliant job.
    I love the clean lines and the crispness of that hull.
    Keep up the good work.

    Martin555.
    Liked by BOATSHED and Cashrc and
  2. CashrcGold
    Admiral
    I decided to pull the 540 in lieu of an new old stock Goldberg “Turbo 550” I had built an old Goldberg Mirage airplane a few years ago and used a brushless outrunner to power it, the 550 motor was included in the kit. The Carl Goldberg company used that motor in both the Mirage and Electra sailplanes, when I was an avid aviation modeler I built both. I had built a Mirage while station in Germany in 88-92, and the 550 powered that plane nicely on 6 cells, even back then. It’s a long can motor similar to the EF76II that came in the PT15, but I suspect it’s a hotter wind, 27 turn or possibly 24, as it winds up considerably better on 7.2 volts. Hopefully I’ll have a decent turn of speed on 6 nimh or 2 lipos, if not I might do a brushless swap or a hotter open end bell brushed motor....or just go to a three cell lipo and see how long the motor lasts🤣
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Yee-ha!!! Paint!

Got the hull where I could get some paint on it, used Tamiya’s Luftwaffe light green and Medium ghost gray. I did the waterline first, then a light primer topside to help find any blemishes, then sprayed the gray. It came out pretty good, still have a couple of touch ups but I’m happy for now. Next up is going to be the superstructure and guns...
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Superstructure, or my love/hate affair with plastic

Hi y’all. Past few working sessions on the PT15 have been spent building the main superstructure. This is probably one of the hardest parts of the build, in my opinion. I just builds...weird. The main body is of some clear plastic, not abs, don’t think it’s Lexan either...it’s also a little on the brittle side. Anyway, once the main body has been cut out, the builder gets the joy of adding the door buckets, the aft superstructure, the fwd entryway, and all the inner supports, bulkhead and reinforcements. I found that either epoxy or Stabilit is the way to go here. Once I had that built, I decided to go ahead and build the aft ventilators and install them. I need to lightly sand the whole structure with very fine sandpaper, I have some 1000 grit on hand for that, then touch up my joints if need be and mask and paint. I’m not real happy with it, the aft cabin is a little swaybacked, but the way it’s glued in don’t know if I can adjust it. I think itll look good once it’s painted and detailed, most people won’t notice it but I know it’s there....😠
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6 comments
  1. CashrcGold
    Admiral
    You paint the exterior...Robbe did something similar with my San Remo’s cabin top, it’s made of the same material. It’s what they do,or did I should say. Come to think of it my Acapulco’s cabin is done up the same way too.
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Painted superstructure

Hi y’all..got the superstructure masked and painted tonight..need to touch it up a bit but overall I’m pleased with it, didn’t muck it up as bad as I thought. Now I have just over 140 more small parts to build, paint and install!! Yay🤣!
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6 comments
  1. MouldBuilder
    Admiral
    Looking really nice. I am making a Robbe kit with a similar cabin structure. I have found this part to be tricky. I have had the most difficulty in placing the masks over the windows.
    The paint job looks really good.😊
    Liked by BOATSHED and Martin555
  2. CashrcGold
    Admiral
    Hi Mouldbuilder! I agree with you, masking isn’t fun. My saving grace is Tamiya masking tape in different widths and some tape sold over her called “Frogtape”. That tape will not bleed, and really gives one a sharp line.
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More superstructure details

Hi everybody. Got some of the details done on the superstructure...looking better, although there’s a few flaws. However, I might be a bit of a hack, but I know how to camouflage my mistakes🤣 Some of the detail pieces are supposed to be built up from abs and obechi wood. I COULD have done that, but then you have to fill the wood with a filler, sand, repeat, etc, all on a piece smaller than my fingernail. To me, it was easier to do a “midnight requisition “ on some of Graces old Legos (with her permission of course) cut down to shape and painted. I’m going to get most of the rest of the bigger projects done, then I’ll do the tiny fiddly bits like the door hinges and the cabin vents. I also need to start thinking about any additional functions, if any, such as lights or sound.
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3 comments
  1. RookysailorSilver
    Rear Admiral
    If your like me Cash, I love all the little detail work on grey boats! I know there's more to break off when sailing, but the detail makes the craft more like the real one, and that's what we all strive for, you are doing a brilliant job,keep it up, figuratively speaking!👍

    Cheers, Pete
    Liked by BOATSHED and Cashrc and

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Railing at the rails!!

Hi all. Did a bit more the past few evenings, got most of the railing installed. I really think next time I build a boat with hand rails and the like I’ll build up the superstructure, locate and drill all the holes THEN paint the cabin and install the railings after. I think 20 percent of the time I have in this is correcting any scratches and errant glue dobs that seem to haunt my work. Anyhow, a couple more small details then it’s antennas and mast.
Cash
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1 comment
  1. Martin555
    Fleet Admiral
    Hi Cash,
    To me the detail work is the most interesting part of the build and starts to bring the boat alive.
    You are certainly starting to bring you'r boat alive.
    Well done, nice work.

    Martin555.
    Liked by BOATSHED and jbkiwi

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Aerials and masts

Hi everybody!!! Great weekend so far, drove the Studebaker this morning, saw “Ford vs Ferrari” with my family (great movie btw) and had time to work on the PT. I did the side aerials last night, got the mast about half done today. Now, if you’ve kept up with this blog you’ll find that I just don’t like making small detail parts from wood, unless it’s supposed to look like wood. The side aerials are supposed to be glued into small pieces of wood that are rounded and fitted to the side of the fwd cabin so that the aerials are about a 20 degree angle. Nope. Not doing that. I have a small stock of various sizes of carbon tube, it was easier and I think, better looking to cut a small piece, sand the angle in, glue that to the cabin and insert the wire for the aerial. Also, Robbe recommends that you put a loop in the aerial end for safety. I used small thrust buttons for rubber model planes glued to the tip. I think that looks better.
The mast was started today, I substituted 5mm carbon tube in lieu of the 5mm wood dowel, everything else is kit supplied. I think the superstructure will be done by Monday evening, maybe Wednesday latest.
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1 comment
  1. Martin555
    Fleet Admiral
    Very nice work Cash.
    With all of those aerials fitted please be careful that you don't poke your eye out.

    Martin555.
    Liked by BOATSHED

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Superstructure done (for now)

Hi everybody. Will keep this short and sweet, have to hit the hay. Superstructure pretty well done, mast installed and a couple of details added, and I decided to go ahead and install the running lights. She’s looking almost shipshape now!!
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Cashrc #10 of 17

Some deck fittings

Hi all. Got a bit more done the past couple of nights. Built and installed one hatch, glued and painted ammo cans and built the life raft canister supports, painted canisters and installed the assembly’s. Working on torpedos now.
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