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Ok some more positive progress and news atleast.

Today I met up with my friend Mike Pendlebury who's actually building my 1/12th Trent Lifeboat. They guys an absolute genius. I mentioned the issues I've been having with line up of the running gear and we got the tug on the bench and had an in depth look. My forward motor mounts were fine however some adjustment was needed on the angle at which they were presented. The MDF board was first glued to the base of the hull.

The motor mounts were in the wrong position previously so new holes were made in order to be able to sit the mounts onto the MDF board. They were then screwed and fibreglassed in place.

During the previous few days of going to Mike's, I was browsing Mobile Marine Models website and noticed I did infact have the 'Kort Eze' shafts. The chunky bit on the end of the shaft is designed to come off in order to remove the kort nozzles themselves. We were puzzled at how they came off but after a phone call to Bryan at MMM, he very helpfully sent us an email containing the instructions (which I never was given when I got the tug). It's a simple job of getting a suitably size spanner which fits over the main shaft tube but not the chunky bit and hitting it with a hammer.

The Kort Eze then came away with very little issue.

And a closeup of the Kort Eze.

If you remember the jig I made using bits of wood and clamps at the start of the build, well we essentially re-created this on Mike's workbench in order to line up the korts. This time a reference could be taken from the end of the shaft tube as the Kort Eze had been removed. It was then fairly easy to work out if the korts would be able to be removed. We opted to use the existing holes I made in the hull however the gap between the front of the kort and the end of the shaft tube was a little larger than what it should be however its a small compromise. Atleast there's plenty of room to get the things out should I need to.

And with the Kort Eze loosely pushed on...

We carefully reset the jig to ensure both korts had the same angle and spacing between the internal surface and the props. The supports were tacked into place with superglue and then fibreglassed in when we knew it was correct.

So what went wrong?

Well, firstly one prop shaft tube is around 1-2mm forward of the other one. This could be down to a small difference in the shaft length however its not an issue - anymore!

Secondly, the hull shape is not entirely symmetrical on each side thus throwing measurements out slightly.

Thirdly, the castings of the kort nozzles are simply not right or consistent. It's very much a case of luck to get the shaft perfectly perpendicular to the rest of the nozzle during assembly. The internal surfaces of the nozzles are seemingly not uniform given when they turn, they still catch on the props despite them being perfectly centered. As a result, some time will have to be taken to sand off a considerable amount of material in order to stop this. More on that in another update.

On the whole a very productive day which now will allow me to progress with the build.

Next steps are to fettle the korts, repaint were necessary, install korts and oil up the shafts and running gear and finally start on electrics.

Moving forward... I've not really accomplished a great amount to be honest but have instead been taking care of some smaller jobs in between the time I have free.Firstly with the korts now sorted, I decided to give the tug a bath... I wanted to see how much ballast is actually needed to drop the boat onto the waterline... I installed the spare (broken) kort while the paint was curing on my other new one.

The motors are now installed in the tug and will be staying there. They help the ballast but not a great deal. The stern:

The bow, And yes... water level is below the bow thruster port...

er... yes it just about fits in the bath. Please excuse the horrendous black tiles, they were there when I moved in. The batteries were then placed into the rough area they will be located and positioned to equally balance the tug in the roll.

Results... Well the waterline at the bow now sits just below the bow thruster port and the stern has lifted even higher as expected. I have some lead weights I put in as a laugh, possibly in the region of 20-30kg aswell as all of the electronics and motors for the winches and she still needed more. I need a way to be able to remove weight from the stern without using the read deck hatch as I have plans for this. I feel I may have to compromise somewhere on her ride height here. I guess it depends on the mission, she can sit high but this may incur instability issues etc. I'll wait and see what the sea trials bring.

I mentioned the korts a little earlier. During my time at Mike's, I realised we didn't fully screw the shafts back into the motor couplings. I did this and tried the korts over the props and they now seem fine. There's one small area on one which looks a little bit too close to the blade - proving what I said earlier. Anyway, I use a flap wheel on the kort and ground the affected area down.

This was then repainted. While the korts were off, I decided to spray up the anodes in Mr Hobby's aluminium. I first had to mask them off. I used the lighter tack frog tape as a test, having only used it for house decorating.

And the finished result...

I have spent the evening just before this update doing some small soldering jobs on the motors. Standard Tamiya connectors are used here. Port side its under normal polarity for motor direction and Starboard is reversed and so to make things easier, the wires were reversed on the plugs so everything is normal upto the female connector.

Having just installed a new utility room set of units, I have plenty of cardboard packaging left over. I decided to get one with making a stand for the tug. I normally hate this task to be honest. The hull shape is pretty simple on the FT-X and so I tried laying the boat on its side and simply scribing the shape onto some cardboard.

This will then be transferred to some 5mm MDF type material (off cut from a kitchen unit back) and cut out. This will then be shaped to fit and then used and stored as a template in order to make the stand out of some bulkier material.

I managed to quickly build a stand just before Christmas.

It will atleast keep the boat relatively level but most importantly, stable.

Not had a great amount of time to work on the boat since I built the stand, but today I decided to press on with installing other parts of the battery compartment.

The next pressing matter is the design and installation of the electrical system. I'm not very good at imagining how this is going to look and this is what I have been thinking about for months. I think its time to just get on with it and do the best I can. I want it to be neat and reliable.

I decided to utilise the space in the bow to mount some major components. The first stage was to find the shape using card in order to use this as a template for some more MDF at a later stage.

Unlike any of my other builds, I want to make the components sectional in the way that I can literally unscrew a shelf full of speed controllers etc, hence the need for so many tamiya connectors.

In other news, I today have ordered the pulleys and belts from Motionco. These are for the bow thrusters, having decided where they will sit in the bow. More on this in a future update.

26/02/2016

Time for another update. The shelf for some of the electronics was made from 6mm MDF.

A support for the shelf was also cut and fibre glassed to the inside of the bow.

The hardest bit for me was deciding upon the layout of the electronics. Historically i've always tried to make them look as neat as possible but it's always somehow got out of hand and started to look like spaghetti. To explain what components are being used here:

The black things at the back are speed controllers, They are ACTion Electronics P98's. One for each motor which will be controlled via a single throttle input. There really is no need to tank steer this thing with bow thrusters and movable korts. More info on them here - ACTion P98

The fuse board is an ACTion P102. It essentially has three different circuits on there which are all fused. This adds a great level of protection and fault tolerance. Group one is the left green socket. Group two is number two and three sockets from the left and finally group 3 are sockets four and five. If say the port motor fuse blew (for example the prop was fouled on something, the instant it is brought to a halt will cause a current surge. If the current is more than the designated fuse then it blows to protect the speed controllers etc. It then allows the boat to limp home on the other motor. More info on the board here - ACTion P102

And finally the Electronize FR15HVR-AN is another speed controller which is responsible for the bow thrusters. It was explained by the manufacturers of the tug that if a standard speed controller was used in the normal way, then the sheer of the thrust off them in tests could flip the tug over. This is because the tubes come out of the bottom of the tug and the sucking and pushing combination massively upsets the tug. The only way round this was to use a specific type of speed controller wired so that there was constant positive current to the motors and the blue and yellow wires which were typically both connected to a single motor to determine forwards and backwards operation were instead used as switching negatives. The wiring is shown below.

And underneath the shelf the wires are connected using choc blocks. The two female connectors will plug into each respective male connector.


A preview of how the shelf is looking.

A On/Off switch was added and soldered in on the underside of the shelf. This will switch power on the main drive of the tug, essentially everything shown above.

Meanwhile the BEC wires were coiled up under the shelf also as they are not needed. The BEC is the Battery Eliminator Circuit. It will spit out 5 volts to power the radio reciever instead of having to use its own dedicated 5 volt battery. The ends will be insulated when I get some small enough heat shrink.


And the Switch on the topside.

Some cables were made up to connect the speed controllers to the motors.

 

 

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©Dan Walker