Scratch build of a fast bulker

Started by ubay93

6 updates 0 likes 15 comments

Scratch build of a fast bulker

My plan was to use 2 old 12v electric scooter batteries to power this monster with a total of 9AH which would have enough power to run for hours, after attempting to charge them after 4 years they weren't holding charge so I popped the caps off and filled them with water and tried to recharge not sure if that was the best idea as the rubber caps kept blowing the plastic cover off. I ended up placing some heavy tools to prevent this but to be on the safe side I will buy some new ones along with a new trickle charger as my current one is a 24v charger.

I have received the rudder, Brass Propeller (30mm), prop shaft (5 inch), coupling and 545 dc brushed motor, I am still awaiting the ESC and controller/reciever.

I am undecided wether to add a front thruster or no thruster so I am building without one (for now) but leave enough space if I change my min later one, therefore access will be build in to provide this at a later date.

I will add as many pictures throughout the build as I can if anyone is interested.

This is my first scratch build.

All pictures will be placed here:

https://onedrive.live.com/redir?resid=DF8F7BD53C500248!4301&authkey=!ADNtjMGYgP0Q-mg&ithint=folder%2c
3 comments
  1. Dave M
    Vice Admiral
    HI Ubay
    Welcome to the site.
    The rubber caps on your SLA batteries are a safety device and should not be covered whilst charging. if the cells gas an explosive gas (hydrogen) can be produced so I suggest you do not continue with this idea. SLA batteries need a special constant voltage charger and should not be charges with a car battery charger, there are many trickle chargers available that will safely charge your new SLA's.

    I think a bow thruster would be a good addition to this model as it will be difficult to dock in any sort of breeze unless you have tug assistance.

    Looking at your pics I can see you have already fitted cardboard formers to the hull. I have built many models with fiberglass hulls and usually run longitudinal stringers round the inside of the hull to keep everything square and provide a base for the decks. You may find that the hull has flexed in once you removed the flange casting. You can still apply stringers between your formers to keep the hull sides flat if these have been fixed in place. A straight edge along the outside of the hull should help you, but do follow any natural curve.

    The markings on the hull are meant as a guide and are rarely spot on. Looking at your rudder it is slightly out of alignment but the model will sail OK with this positioning. The alternative would be to open the rudder hole with a file so that the alignment was central. You can make good the damage with some body filler as used on your prop shaft.

    You are progressing well and please keep the pics and info coming 😀
  2. joergn
    Able Seaman
    Hi,
    Just wondering how many degrees does that layout get for the rudder. Guess would be cool. Just wondering cause my next build is a m barge, the barge it's self is called 45m Irish in land water...... it's still only rattling around my head at the min.
    The real rudder give 180 deg by hand.

    Nice boat
    Joe

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Wood Arrived

Yesterday I went out and bought a massive 3.6mm thick panel of plywood, only to real ease that the only ones in stock were either water damaged and cracked or discoloured and flaking so as all bargain hunters do I got 50% for the damage and the guy serving me said it should of been put in the skip, but its good enough for me.

The wood has been cut by the distributor down to the smallest they could get to my needs but still quite a bit off plenty of hand sawing for me :/

Today I got around to cutting and shaping the aft deck which is going well but the fibreglass shell is not even so I have decided to form the wood with my templates and will then patch fill at the end with a pva/wood powder mix.

On a side note the Servo also arrived today

New pics have been uploaded

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Prop shaft and rudder stock

Today I have affixed the motor mount, propshaft and rudder stock to the hull of the model,

The rudder stock I decided was to long so I have cut it down and to prevent undue stress on the thin hull I have placed a piece of wood across it to prevent any bending stress.

I have created some more cardboard templates for wood to be cut, but I can't cut anymore wood as all I have used so far is a hacksaw and a rotary tool with its horrible cutting bits which is just burning the wood, therefore I have placed an order for some new cutting bits that are designed for wood. I was going to buy a coping saw but to get straight lines especially for the main deck I decided for the new cutting bits.

The hull itself has been sanded down to get rid of all the bumpy edges and I have been in contact with a paint shop to see what paint I should use for the fibreglass and hull itself.

I have decided that the propshaft needs some support to reduce vibrations.Therefore it has been supported with some scrap wood it looks terrible but it won't be seen once the mount for the servo has been placed over it.

All in all its going slow but once the cutting bits arrive and the bloody transmitter / receiver gets delivered I will have the underwater bits ready for water testing, before I start on the superstructure and details.

Lessons learnt so far.
1) Always use high grit (320 ) wet sandpaper to fibreglass as the dust is horrible and gets everywhere

2) Always use cardboard of the same thickness of wood to be used for templates otherwise they give the wrong dimensions. :@

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Build coming along nicely

I have cut the bulkheads, main deck and hatch covers which admittedly are a little small (not my fault as I didn't cut these pieces.

All of my electrics have been delivered and tested, all work fine but the controller seems to have a dead spot in the first 20-30% of stroke for the motor in any channel yet it works fine for the servo on all the channels :/. I have connected a voltmeter and its not pulling anything till about 30% through the stick travel for the motor, I will have to connect the controller to the pc to see if I can adjust some of the settings to rectify this.

admittedly I did have an accident in which I did the electrics test in the bath and let go of the boat and it sank with the electric's in the base grrrrr.

The servo mount and rudder are completely finished. I used an old prop shaft from another kit project for the connector arms.

new pics have been added to the onedrive folder
2 comments
  1. Dave M
    Vice Admiral
    Good progress being made.
    Are you going to leave the rear deck free to lift off or adding a hatch to allow access to the rudder? I can guarantee you will need access at some time so now is a good time to make the arrangements.
    What motor controller are you using? many auto-setup on switch on so you should have your transmitter on before connecting the receiver battery and ESC.

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ESC Problems

HI all

I was wondering if someone could help me with my Esc, I have attached a video of the problem. Within the video I have powered the motor 3 times. The motor is rotating freely but with friction the coupling is trying to rotate.
1st, 100% power at full stoke
2nd, 50% at full stroke (controlled by a switch)
3rd, close up of motor at 50% full stroke

There is a lag between me wanting power and power being delivered as well as a high pitched beep? Can anyone see why? I am pretty sure it's the ESC, it's defiantly not the controller as with servos the stroke works correctly.

https://onedrive.live.com/redir?resid=DF8F7BD53C500248!4393&authkey=!AL4fYvdcDcZDRAY&ithint=video%2c.mp4
9 comments
  1. Dave M
    Vice Admiral
    Yes this should suit fine. This is the latest Tio version brought in to allow safe use of LiPo batteries so has additional cut out features.
    For your 12v SLA you could use the earlier version of their 15amp ESC which would work just as well. They are selling ex demo versions at £18 and I have bought and used several with 12v SLA's and they work fine. 👍

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Main deck supports

I have taken the advice from earlier and put some longitudaul beams along the main deck, I have finished the hatch covers, main deck, quarter deck and transverse bulkheads (almost), a test fit of all the pieces are alright still some fine tuning before the pieces are glued together everything has to be correct before gluing.

I have also decided to paint the hull and all pieces before gluing them to ensure complete coverage (I will sand the bits where glue will be applied)

I cant decide on colours I am thinking dark maroon for beneath the water line and dark grey for the rest of the hull. Dark grey main deck/quarterdeck and a white superstructure and hatchcovers. Any input or reccomendations would be great.
1 comment
  1. Dave M
    Vice Admiral
    Hull looking good. The stringers have certainly helped keep everything ship shape.
    Your chosen paint colours should work well together. Have you any pics of an original to give you a clue as to actual colours? if not then just use colours that appear correct and suit your preference. Working boats usually were not pristine in their paint finishes so you may want to avoid using high gloss in favour of a more satin or matt finish. I usually finish my models with a satin clear cote that flattens all the colours and provides protection against the odd knock and sticky finger marks. 😀

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ubay93 Opening post

Scratch build of a fast bulker

I have done a lot since my last update sorry, all major parts have been painted and epoxied In, I never realised how amazing epoxy putty Is to put around frames, just roll It up and apply like bath sealant. each hold Is now waterproof to the waterline/holes drilled for the wires to pass through, the hull has been painted, If I'm honest I didn't do It very well, It was going ok at first then the masking tape just ruined It the paint sealed through and peeling off the masking tape was horrible It was just pulling the paint off (I waited 24 hours before removal). anyway the bit you will never sea (under the water Is amazingly smooth just the bit above water Is bad).

I have spent many hours soldering deans connectors and finally finished It all this morning wired It all up for a test and frazzle, I ended up getting confused with the many connectors and connected the motor side of the esc to battery, now It just powers the bed and no response to throttle control so Its good for the bin ( I won't throw It out I will keep It as It could be used In the future for pure BEC power) I have uploaded photos but don't forget this Is my first build and I have learned quite a lot so far.

All thats left Is cutting foam to place In the holds to reduce the risk of sinking the detail and a water test, I have tried a flooding test before I put all the components In and apart from a few dribbles passing through Its ok.

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