Another Golo Build

Discussion in 'Warship Builds' started by tgdavies, Sep 29, 2012.

  1. tgdavies

    tgdavies Member

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    Having learnt a lot about all aspects of model ship building from my tug, I decided to build a battleworthy transport as my next ship -- the Golo seemed like a nice size. I'm building to Australian Battle Group rules.

    I want to get more experience in the 'Quick Fibreglass Hull' method, so I decided to use that again. I'm using West Systems epoxy resin rather than CA -- while I was happy with using CA, I think a longer working time will help me get a neater result.

    Most builds I read about in this forum seem to be wooden hulls. I've never built one, but the process of cutting the inside and outside profile of each rib, plus notching them accurately, looks pretty time consuming compared to just cutting the outside profile out of 5mm balsa (although I would like something even easier to cut than balsa, which is unnecessarily strong, except along the grain, where it can be too weak).

    [​IMG]

    I learnt from my first build that if you are building a hull with sheer, don't try to bend the subdeck and build on top of that -- the bend will be wrong, and so will the relative heights of your ribs. Pretty obvious really :) This build just has 'legs' on the ribs so that when glued (upside down) to the building board the keel is straight. I didn't give the highest part of the hull (the bow) 'legs' -- so the deck line touches the building board here. That was a mistake -- it made getting the fibreglass cleanly onto the hull very hard. In future I'll make sure that all decks are at least 10mm clear of the building board.

    The ship is skinned with 0.4mm plywood, and where that isn't flexible enough, 1.2mm balsa. You can see the finished sheeting in the photo below. I have filled some gaps, which was probably a complete waste of effort! The skeg (which is simple in the Golo as it's a twin shaft ship) is 2mm styrene.

    [​IMG]

    Here's the ship in its current state: One layer of 6oz (200g) fibreglass on the outside, and another on the inside, marked up for the cutting out of penetrable areas, once my oscillating tool (a Bosch PMF 180E) arrives.

    [​IMG]

    Plenty more work to go:

    - reinforcing the ribs with another layer of fibreglass
    - fitting the subdeck. The forecastle will just have a deck, as I don't need access under there, the rest will use 2mm styrene with some fibreglass reinforcement, as an experiment.
    - fitting stuffing tubes. The Golo has quite a large hull extension around its shafts (what's the nautical name for that?) which I may or my not bother modelling.
    - fitting the rudder
    - decks -- I'm going to use 3mm Sintra (PVC foam) for decks, other than the fixed 2mm styrene forecastle deck.
    - superstructure -- 3mm Sintra again.

    and of course motors -- 28mm brushless, pump -- not sure where I'll get that yet, and other electricals.
     
  2. tgdavies

    tgdavies Member

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    Here it is with the windows cut -- it's almost traumatic to take a nice looking hull and reduce it to a lacework!
    [​IMG]
    The Bosch PMF 180E is not the ideal tool for this -- it's too big and powerful. I was put off the Dremel equivalent by some Amazon reviewers saying it was not robust enough, but I suspect they had more demanding uses, I expect it would handle this fine. There is a 65mm radius cutter available for the Bosch, which would be a bit nicer.
    Next I'll reinforce the ribs (although they don't feel terribly weak) and fit the stuffing tubes and rudder.

    I've started work on bits of superstructure, out of 3mm Sintra and 1mm Styrene -- only time will tell how well that will stand up to battle...

    [​IMG]
     
  3. tgdavies

    tgdavies Member

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    I've reinforced the ribs with another layer of fibreglass. While it is a lot simpler and quicker to lay a few strips than it is to lay another entire layer, I wish that I had marked the ribs on the inside of the hull and done the reinforcement *before* cutting the penetrable windows. That way there wouldn't have been an extra step of trimming the reinforcing.
    I have also fitted the rudder. I cut the rudder from thin (about 0.5mm?) brass sheet, cut a slit in a 3mm brass tube and soldered them together with ordinary electronics solder on my kitchen gas stove. The rudder was a tight press fit into the slit, so I heated the two parts already assembled, touched some solder to them, which melted but balled up and didn't flow, even though it was sticking in about the right place. I then returned the rudder to the flame and heated it until the solder melted again and wicked into the gap.
    The rudder runs inside a 4mm brass tube, about 15mm long, which I've epoxied into the hull with Selleys "Knead It" Epoxy Putty (the sort that comes in a sausage with the hardener in the middle).
    I've also drilled the holes for the stuffing tubes, so the next job is to finish fabricating the motor mount (just a bit of aluminium angle) and putty the stuffing tubes into the hull. I'm going to fully assemble the drive train to make sure that I get everything lined up.
    Here's a photo of the rudder in situ: http://www.flickr.com/photos/41886002@N05/8099608129/
     
  4. tgdavies

    tgdavies Member

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  5. Tugboat

    Tugboat Facilitator RCWC Staff Admiral (Supporter)

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    Coming along nicely, Tom :)
    I have used epoxy and plumbers goop for motor and shaft mountings... silicon might not be good over time, but how often do you use a convoy? If frequently, might want something more durable. If only at Nats, Silicon might do it.
     
  6. tgdavies

    tgdavies Member

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    I'm expecting my Golo to get used (and sunk!) at every battle -- especially as I don't have a warship yet.
    I ended up epoxying the motor mount to the hull.
    Further progress:
    - I've mounted the rudder servo in a frame made on 3mm Sintra -- it feels strong, but next time I have some fibreglass epoxy resin mixed up I'm planning to add some reinforcing. The servo arm is connected to the rudder are by a strip of thin brass, which has plenty of rigidity. I'm getting about 50 degrees of rudder movement to each side, which I hope is enough for maximum manoueverability.
    www.flickr.com/photos/41886002@N05/...hotostream
    - Fitted bullet connectors to the motors and test them, seem fine.
    - Epoxied in the forecastle deck. Because I don't need access under the forecastle I haven't bothered with a subdeck/removable deck arrangement -- it's just a 2mm styrene deck epoxied to the hull. To get the positioning correct I CA glued some small Sintra blocks to the hull first.
    www.flickr.com/photos/41886002@N05/...hotostream
    www.flickr.com/photos/41886002@N05/...hotostream
    The only possible concern for this is if I decide to fit a blast shield to stop double penetrations in the bow area -- the fixed deck may make that a bit fiddly.
     
  7. joe thomer

    joe thomer Active Member

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    good pic and info on the build.
    questions: are the engine motors brushless?
    also...the universal joints (not dog bone)...were did you get them?
     
  8. tgdavies

    tgdavies Member

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    They are brushless -- http://www.hobbyking.com/hobbyking/...oduct=8622 -- I think that they are overkill for this ship, I would have used one and a gearbox if I had been able to easily source a gearbox.
    The universal joints come from http://www.cornwallmodelboats.co.uk -- they have a good range of reasonably priced stuffing tubes, props and rudder arms (and a bunch of other stuff), and their shipping is reasonable (I'm not sure if there are better options for US residents, but I'm in Australia).
    Tom
     
  9. tgdavies

    tgdavies Member

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    I've now fitted the subdecks -- the midships subdeck is 2mm styrene with 200g fibreglass backing -- which didn't work too well as the resin didn't stick very well, and the aft subdeck is 3mm Sintra. I'm planning to add a fibreglass 'hinge' between the bottom of the subdeck and the side of the hull, if I can be bothered.

    http://www.flickr.com/photos/41886002@N05/8178552608/

    This is much lighter construction than other builds I've seen -- 6mm plywood subdecks, with screws through the hull holding them in place seems more normal. My build feels rigid, we'll see how durable it is!
     
  10. tgdavies

    tgdavies Member

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    I've completed sheeting the Golo -- at least the first stage.
    www.flickr.com/photos/41886002@N05/8198826005/
    The sheeting is done in 1.6mm balsawood. I cut a separate panel for each window, which might have been unnecessary if I had been more careful in selecting my balsa -- I should have gone through the selection at my local hobby shop and chosen the sheets which were most flexible.
    My technique was this:
    - Cut a section of balsa to fit -- I overlapped by about 5mm around the bottom and sides of the penetrable window, and went all the way to the deck rim above.
    - Spray the back of the balsa with CA kicker.
    - Spread thick CA glue onto the hull around the window and up to the deck rim. (I tried some windows with thin CA, but that dripped off the places I wanted it onto places I didn't)
    - Press the balsa onto the hull, starting at the top and making sure that the panel is smoothed progressively into place.
    The panels are proud of the hull and will need some sanding and filling to give a neat result:
    www.flickr.com/photos/41886002@N05/...079950600/
    After I have a reasonable finish I will silkspan the hull.
    Some people use pre-silkspanned balsa at this stage. You can attach the balsa with the silkspan on the inner face, as when it is on the outer face sanding becomes difficult -- the silkspan doesn't sand well. As the AUSBG rules only permit solkspan on one side, and as I want to patch battle damage with silkspan, I decided to put the silkspan on the outer surface, after sanding.
    I've also found a nice stainless steel M3 U bolt for my float attachment point.
     
  11. NickMyers

    NickMyers Admin RCWC Staff

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    In the future, you could probably save yourself some time and do the majority of the hull with a single sheet - looking at your hullform, probably the first 5 panels without much trouble.
     
  12. tgdavies

    tgdavies Member

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    Nick, my balsa was not very flexible -- also my penetrable windows go to the turn of the bilge, and once you have such a sharp bend in one dimension its hard to get any flexibility in the other... But yes, it would have saved a fair bit of work.

    The filling and sanding is in progress, meanwhile here's the hardware for the hull side of the float connection: http://www.flickr.com/photos/418860...hotostream

    I found a stainless steel M3 U bolt, normally used for securing wire rope. I've made two brass plates which will sandwich the hull and hopefully distribute the load sufficiently. I'll use Nylocks to keep it secure.

    Not sure what I'll use on the float -- something less heavy duty.
     
  13. Tugboat

    Tugboat Facilitator RCWC Staff Admiral (Supporter)

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    As long as you're not jerking upwards on the tether, the brass plates should be plenty of weight distribution for a slow, steady retrieval. Especially for a smaller ship like a Golo.
     
  14. tgdavies

    tgdavies Member

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    I finished fairing the balsa to the hull -- a bit of sanding, and a fair bit of filling.

    I used Squadron Green putty in some places (that's the green bits) and some Selleys Knead It epoxy putty (the grey parts). I wasn't too happy with either -- the green putty feels as though it will chip pretty easily, and the epoxy is too hard to sand and has too short a working time. I might try automotive spot putty next time. What do other people use?

    I've also silkspanned the balsa on the outside only. I didn't bother with the more elaborate methods -- just cut the silkspan roughly to size and painted it on, smoothing out any minor wrinkles as I went. It was straightforward.

    [​IMG]

    I've attached the U-bolt:


    [​IMG]


    Not very pretty on the underside, but I do want to recover my ship!

    I've also done the first float test (no, I don't have a filthy bathtub -- just sandy kids!) -- I was pleasantly surprised that my giant 8.4Ah LiFe wasn't too heavy, despite my unnecessarily long stuffing tubes forcing me to put it quite far forward. There was a slight leak around one of the stuffing tubes, so I've sealed that with some CA glue.



    [​IMG]
     
  15. rcengr

    rcengr Vendor

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    After trying and failing several different brands of wood spackling (they don't like getting wet) I have gone to automotive spot putty and found that it works pretty well. The Golo is looking great.
     
  16. joe thomer

    joe thomer Active Member

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    how about pic of the inside of the boat to see the recovery system
     
  17. tgdavies

    tgdavies Member

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    Here's the inside of the recovery attachment point. There's another brass plate, the same as on the outside, this one epoxied to the hull, with M3 nylock nuts clamping it against the hull. I think it will be strong enough.
    The cord will pass through a block of foam and be attached to the underside of the deck (the foam will also be attached to the deck).
    [​IMG]
     
  18. joe thomer

    joe thomer Active Member

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    thx for the pic, looks good
     
  19. tgdavies

    tgdavies Member

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    I realise I could have got the u-bolts more cheaply here: http://www.ebay.com.au/itm/3-25-3mm-304-Stainless-Steel-U-Shape-Bolt-Wire-Rope-Clip-Cable-Clamp-5-Pcs-/350616707196#ht_1668wt_810 (I just discarded the 'saddle' part)
     
  20. tgdavies

    tgdavies Member

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    Black is such a common colour for the hulls of merchant ships, so I decided to go for Gentle Lavender, aka Union Castle Lavender. Not historically accurate, as (I believe) that freighters operated by the Union Castle line had black hulls, only the liners getting Lavender, but I like it.
    Now I need to decide what colour to do the decks -- I'm not sure if the Golo would have had wooden decks or metal decks, and if the latter, what colours are appropriate... I also need to decide whether to try covering my Sintra superstructure with fibreglass, or just resign myself to an early refit when it gets shot to bits.
    [​IMG]