Topic: 1/12 Salcombe Tamar (Read 65421 times)

CJ1 · « **on:** May 02, 2010, 03:17:20 pm »

Well, at last, I've started my Speedline Tamar properly!
As this is my first electric boat, I started by wiring up the electrics out of the boat and test running everything in a wood test rig to get to understand them.
The shafts went in very well with the help of the jigs that Adrian (of Speedline) recommends. I used ply to make the supporting fillets inside and out and epoxied these in place. It was difficult seeing what shape the external supports should be, but on closer inspection of the RNLI drawings (thanks Phil for getting me to buy those) I realised they are shown on one of the sheets.
I've now spent the last couple of days trying to make a plywood mount for the motors to install them in line with the shafts. This is my first time putting electric motors in a boat and aligning two 1lb. motors (Graupner speed 900s) to two prop shafts and to the inside of the hull with it's 3D shape with only two hands and a dozen packing pieces, taxed my little brain somewhat. Nowhere in this forum does it tell you how tricky it is! Is this a conspiracy against new modellers so as not to put them off. All ideas for this and future problems are more than welcome here.
But....how satisfying when it all goes into place. The front support for the bow thruster battery and esc. was much quicker, and the test float in the bath to decide roughly where to place the main 12v batteries comes later this evening!
The window frames are made, the holes marked up in the cabin side, and I have a trip to the Salcombe lifeboat next week to get detail photos for the Y-boat that I am making alongside the real job.
Looking forward to Wickstead to see other peoples ideas now.

DaveB · « **Reply #1 on:** May 02, 2010, 06:31:53 pm »

Hello CJ1
Have a look on mobile marine models web site they do a prop shaft/motor alignment jig and will do special sizes if necessary.
Dave

CJ1 · « **Reply #2 on:** May 10, 2010, 07:26:12 pm »

Dave,
Thanks for that. I talked it through with my mate who has a lathe, and hey presto, 10 minutes later, a brass shaft alligner! Now the universal joints slip onto the motor shafts spot on each time.

CJ1 · « **Reply #3 on:** May 11, 2010, 07:14:50 pm »

With a lot of help from Roger, here are the first build photos of the Salcombe Tamar. The eagle-eyed amongst you will have spotted part of a recent fun birthday present...an Airfix Severn y-boat. Talk about the sublime to the ridiculous!

I have left room on the servo tray above the motors for a servo to open the transom door, if I decide to go down that route. The cross linkages on the rudder stocks are from a plane/helicopter set-up and are very easy to remove yet have very little play in them. I thought with the poor access once the stern garage is in place, I will need all the help I can get for maintenance. I also made the brass rudder horns with this in mind too. I have extended the rudder tubes to above the waterline inside, but with enough space to work on them under the transom garage. With a little grease, this should minimise the water ingress here. I epoxied a ply web behind each tube to make them rigid, and managed to keep the tolerances fine so there is very little play in the rudders but they still turn sweetly.
Chris

rg197r27 · « **Reply #4 on:** May 11, 2010, 10:40:52 pm »

looks good m8 keep up the good work

rich

CJ1 · « **Reply #5 on:** May 15, 2010, 10:39:34 am »

The "bath" launch went well, no leaks and battery position established.
What do I do about washers between the prop. lock nut and the shaft? Will simple brass or stainless ones do?
Chris

CJ1 · « **Reply #6 on:** May 20, 2010, 07:57:00 am »

Having passed the bath test, (hope my wife doesn't see this photo) and found roughly where the batteries need to go for fore and aft trim, I made two trays from ply that I bonded to the hull, outboard and alongside the motor positions. On top of those I've fitted aluminium trays in which the battery sits to stop athwartships movement, but allows me to position them over a large fore and aft position for trim. The batteries are held down by straps with the new velcro that clicks together...often used in model helicopters as it is strong and positive but easy to pull apart when needed. The thought of a 12v 7aH battery rolling around in there was a bit scary.
I have chosen to place the batteries at the sides (rather than along the centreline) to help give the model a better scale roll in non-scale seas. Any ideas on this?

I've deliberately left the wiring long at the moment because I know the moment I shorten and neaten it, I'll find it would have worked better with a different layout. Again, any ideas on my layout would be warmly welcome. Hopefully off to the lake this weekend for it's trial sail (with a temporary cover over that big hole in the stern!).

I am about to start painting the Y boat. I want a matt or satin finish. What can I spray over the Halfords orange to achieve this? I've seen Spectra satin spray...anyone out there know if this is any good over Halfords spray?
Chris

6705russell · « **Reply #7 on:** May 20, 2010, 08:53:07 am »

Hi Chris

Humbrol do a matt spray varnish if thats any use?

Cheers

Russ

CJ1 · « **Reply #8 on:** May 22, 2010, 06:28:03 pm »

The Tamar took to the water for the first time today on a local lake.
The two Graupner Speed 900BB motors push her along easily at scale speed with a good wash from the transom. She has good turning characteristics at speed, and easy low speed manoeuvring with the bow thruster and the two motors on separate channels (I'm not using a mixer).
I underestimated the power of the props though, and in reverse, one of the Graupner universal joints pulled apart, allowing the prop on it's shaft to fall back onto the rudder. I am going to fit colletts with a grub screw around the shafts just ahead of the prop tube inside the boat to stop that happening again....unless there is a better way, anyone?
I am still mystified by electronics though, and when I first set it up at the lakeside, nothing would respond to the controls, despite it working at home one hour previously. I realised that I had put the power wires to the bow thruster motor on the wrong way round, so I reversed them and everything worked properly! How does that work?
Anyway, that's the first major hurdle out of the way, and so now on with the build.
Chris

johno 52-11 · « **Reply #9 on:** May 23, 2010, 01:02:16 pm »

Quote from: Chris J on May 22, 2010, 06:28:03 pm

The Tamar took to the water for the first time today on a local lake.
The two Graupner Speed 900BB motors push her along easily at scale speed with a good wash from the transom. She has good turning characteristics at speed, and easy low speed manoeuvring with the bow thruster and the two motors on separate channels (I'm not using a mixer).

Hi chris,

What calculation are you using for scale speed as knowing what it takes to get a Severn to run at 7.2 Knots (Scale Speed for 1/12) and also running Graupner 900 in my arun I find it hard to believe that 900's on 12Volts could provide enough thrust to push a Tamar at scale speed.

Regards

John

6705russell · « **Reply #10 on:** May 23, 2010, 01:30:54 pm »

I suppose it all depends on what scale of speed you want it to look right at, if it lifts the bow and pushes a nice wave at 3/4 throttle then it should look ok.....

Russ

CJ1 · « **Reply #11 on:** May 23, 2010, 02:02:51 pm »

John,
It's a fair cop! My comments were based purely on visual. The model looked like it looks in real life, in photos and in video. Bows nicely raised, planing but solid in the water, and with a nice amount of white water behind. I was running it without its cabin, but it was doing 6-8 knots. You would have had to jog hard to keep up with it!
I was using the 5 bladed props from the kit, and remember they are working in efficient tunnels on the Tamar.
My mate took a video on his camera and is putting it on disc for me. As soon as I have it, I will post it on YouTube and post a link to it here.
kind regards,
Chris

rg197r27 · « **Reply #12 on:** May 23, 2010, 04:50:55 pm »

i am looking forward to seeing the photos / video

rich

CJ1 · « **Reply #13 on:** July 01, 2010, 12:19:19 pm »

OK, so the boat works, now on to the detail. (Video will follow when I can work out how to post on youtube!)

Having started on the upper helm area, with Adrian's lovely laser cut perspex parts, I assembled the whole stowage wall/mast box structure and glued it in place at the back of the GRP cabin moulding, using it to locate the upper helm/doorway GRP moulding. After a couple of hours of careful manipulation, and then allowing the P38/P40 to set overnight, it looked horrible. I'd had to squeeze it in place and the cabin sides had distorted. Then I realised I had left out some of the perspex detail parts from the mast boxes, and to top it all, I should have fitted the mast supports in place first. That was it, I set to with my dremel and took it all out. Glad I did though, because everything has gone together easily this time.

Looking at the brass parts for the mast, I find it a bit daunting with no instructions or individual part numbers. Trying to match up the tiny parts with the parts on the real boat photos is so time consuming. When I finally do though it is so pleasing. Anyone with knowledge of where it all fits, apply here!

I've been playing with the airbrush to get detail effects, and managed to replicate the air intake effect on the mast box with silver sprayed over matt black. Tamiya masking tape makes life much easier. It gives really crisp edges, and no pulling of the paint.
Chris

CJ1 · « **Reply #14 on:** July 02, 2010, 09:35:50 am »

I've joined the modern world and posted my first you-tube clip!

http://www.youtube.com/watch?v=kXC1aTzLRWw

This is the first run, and doesn't include the part where I lost a propellor as it left the bank for the first time. Fortunately it wedged against the rudder so I was able to reconnect it. However it left me very nervous that day, so I stuck to 3/4 throttle at most for this clip.
Chris

Roger in France · « **Reply #15 on:** July 02, 2010, 01:02:56 pm »

Well done, Chris.

She looks good and steady. I bet you were thrilled to bits.

Roger in France

CJ1 · « **Reply #16 on:** July 07, 2010, 04:24:20 pm »

To everyone making the Speedline Tamar, I am trying to assemble the starboard rope reel box and can't work out which part is the top of it.
Anyone know which sheet it is on?
thanks,
Chris

CJ1 · « **Reply #17 on:** July 08, 2010, 01:44:48 pm »

Quote from: Chris J on July 07, 2010, 04:24:20 pm

To everyone making the Speedline Tamar, I am trying to assemble the starboard rope reel box and can't work out which part is the top of it.
Anyone know which sheet it is on?

OK, found it, it turned out to be a vac-form moulding.
Chris

CJ1 · « **Reply #18 on:** July 13, 2010, 07:29:05 pm »

Q. What do you call a cross between a 3D jigsaw puzzle and a Rubik's Cube?
A. A Tamar cockpit!

..... but so satisfying when it all goes together. Having made the side mast boxes, this time with all of Adrian's excellent perspex parts, and fitted the mast support brackets from the inside (thanks Rich for that tip), painted the port ventilation grill and masked it off to prevent over-painting later, I finally reassembled the cockpit. I also did a test spray first to make sure I could get paint to all the hard-to-reach areas when it was put together. This time the mast support boxes fitted flush and there was no distortion of the side panels. The rope reel box also went together well with it's vac-form top and looks good.

Chris

ps I've just spotted the white duct tape on the cockpit side in the photos. Not a standard feature on Tamars, just me wanting everything to set overnight before I finally release it!

rg197r27 · « **Reply #19 on:** July 13, 2010, 08:28:49 pm »

Looking good m8 glad i could be of help

rich

CJ1 · « **Reply #20 on:** July 23, 2010, 06:37:48 pm »

I've had a go at the three liferafts that fit in the stowage wall.
I made one in wood, took a mould of half of it in silicone and turned the others out in GRP using the mould. I played around with different resins, hence the odd colours!
The decals are home made on the computer and decal paper, but are too white at present. I hope they will tone down after a spray of satin clear. I just need to fit the grab handles in the black patch (I'm right out of 1/12 webbing right now!) and the restraining strap to keep them in place.
Chris

CJ1 · « **Reply #21 on:** November 24, 2010, 08:37:05 pm »

I've got a workshop back again (I had the last one knocked down and rebuilt), so as a reward, I had a day on the Y Boat to try and finish it. Nearly there. I had decided I was going to finish it and get it out of the way before I did anymore to the Tamar itself. I haven't got the right numbers for the Salcombe lifeboat y-boat yet; they will go on later.

For some reason, I can't upload the other photos, so I'll post them later.

Chris

6705russell · « **Reply #22 on:** November 24, 2010, 08:48:52 pm »

Looking good Chris

Russ

CJ1 · « **Reply #23 on:** November 24, 2010, 08:59:18 pm »

Thanks Russ,

OK managed to get the others uploaded now.

Now I'm going to have a go at the transom garage on the Tamar!
Chris

Mark47 · « **Reply #24 on:** November 24, 2010, 10:54:49 pm »

That's a model in its own right!

Superb bit of modelling!

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Author Topic: 1/12 Salcombe Tamar (Read 65421 times)

CJ1

DaveB

CJ1

CJ1

rg197r27

CJ1

CJ1

CJ1

CJ1

rg197r27

CJ1

CJ1

Roger in France

CJ1

CJ1

CJ1

rg197r27

CJ1

CJ1

CJ1

Mark47