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[geoff p]

Hi Fellow Modellers,
On my local pond I have found a beautiful side-pond but access to it is under a very low bridge.  My tug can just get under this bridge by  bumping the mast, thus rolling the boat and gaining the extra half-inch 'clearance'.  Not good practice!

The original vessel's mast could be lowered and I wonder how to replicate this on my model?  If possible under radio control?

What are your views on this?

Geoff

[barryfoote]

Geoff,

Not got a clue how to do it but I'll bet it is possible. Someone will know..A very good question.

[geoff p]

Gee, thanks, Footski  :)

[HS93 (RIP)]

any chance of a picture so we can see what you need , is the hast front / mid   I know the Thames tugs did a similar thing with funnels so they must have had to lower masts at the same time..

Hs93

[geoff p]

I just knew you would want a picture :)
The mast is just forward of the superstructure, and lowers for'ds, to rest in a frame built over the windlass.
This one shows the tabernacle (is that the right term?) on the original boat.

I've just been playing with pulling/slackening the stays via long 'arms' on a servo but have not achieved enough travel to heave the mast upright :(
Geoff

[HS93 (RIP)]

That picture helps greatly so there is no problem lowering it its just what keeps it up have you got a picture of your boat showing where the stays or whatever they are called go to and is there one that goes backward, if so some thin elastic on the front stay and a winch made from a servo on the rear stay to pull it back up would work , just put a bobbin on servo and disconnect the pot and remove the stop so it will turn continually. so another picture please..

Hs93

[HS93 (RIP)]

instead of elastic you could use a double drum one side winding in the other letting out, so you pull it up and down depending on direction. and the base is just a simple pin hinge that could include a switch to stop it.

Hs93

[geoff p]

Up to now I haven't put any stays on the model - the mast is a piece of aluminium tubing shoved over a peg in the deck.  Its primary function, for me, has been to keep the radio aerial from trailing in the water.  So no photos of that part of my model :(

Sorry this picture is not very clear but you can just make out that the stays attach to the edge of the 'bridge', aft of the mast.  There doesn't appear to be a forestay, so the tension in these stays heaves the top of the mast back, and the housing below the pivot pin stops the mast leaning aft too far.


BTW, thanks for your idea of modifying a servo for continuous rotation. I hadn't thought of that.
Geoff

[HS93 (RIP)]

OK dead simple idea , don't mod the servo just get two gears and a belt (toothed) fix to servo and to the mast pivot pin you can get some nice small ones. also fix pivot pin to mast , you should be able to get the servo under the deck and a small cover over the belt .there is a very poor sketch may give an idea. 

http://www.hpcgears.com/

Hs93

[geoff p]

Thanks for that and especially the link to HPC gears.  It would probably take an age to get the bits shipped out to Taiwan so I'm going to try a direct linkage.

With luck I can hide/disguise the links under some 'brück' on deck.
Geoff

[HS93 (RIP)]

Sorry I didn't realise you where out there ,, belt drives and gears are used for buggy's and other model cars so can be sourced from shops selling model car parts.just need to mooch about to get the right size

peter

[chingdevil]

Can you get hold of any cams fit one to a servo set under the deck and a direct arm of piano wire onto the bottom of the mast. That can push the mast and lower it, when the srervo is revered it will pull the mast back up again. If you alter a servo you might find that the mast weight and fulcrum point will overtake it and it will slam down on to the deck.
If you can not get any cams let me know I have some old ones and can send them to you.



Brian

[geoff p]

Thanks for your offer, Chingdevil.
In fact I've cracked it, as these photos show.
I don't want to sit there holding the (whichever) lever on the transmitter to keep the mast up.  So I have elected to have the mast's normal, up, position as servo neutral.  It thus requires a positive action to lower the pole.
My servos only give 45^o of travel from neutral, so the linkage has to effectively multiply 45^o to 90^o which explains the odd sizing of the bellcrank.

Hey, another benefit of the lowering mast, now it should be at less risk when on the motorbike travelling to the pond :) :)
Thanks to all for your interest, now I'll build a deck housing to cover the servo and all.
Geoff

[barryfoote]

A cracking solution to a difficult problem....Only one question....When operating the servo does the mast come up very quickly, thus risking damage or is it operated using a Tx stick, thus giving better control?

[HS93 (RIP)]

very good glad you sorted it out .looks good. if as Footski asks it comes up fast there is a small unit that can go the servo lead to slow it down and they are only cheap, they use them on gun turrets and on planes for landing gear


Peter

[geoff p]

Glad you like it chaps.
The servo is under joystick control and I suspect I will have to practice to make the movements look realistic.  I think the old boys on tugs and barges probably took five to ten minutes raising the beast and shackling the stays an' all an' all.  Somehow, I don't think I'll take that long :)

As for damaging it, I think the mechanism will prove to be the weak point, the mast itself is aluminium tube, 8mm OD x 1mm wall, so it is pretty strong.

BTW, here's the boat in 'transport' mode.  I live about two kilometers from the pond, which distance I travel cautiously.  Must make a sign for the bike - "Please take care, boat on board."
Geoff