Friends..Colleagues..all we know, model War Ships...are  an awesome view, when it rests on stands, and even more awesome, when it cruises in water..with a dark ghost grey, it look agressive and stunning..if so, think a warship mdel with rotating turrets and with an elevating gun on it..!! hooyyy..interesting..but most of the warships are scaled in little scales because of the sheer size of every craft..so, fixing an additional gear box to a slender hull is not a feasible one..so, we adds with a simple micro servo..but most of the time, with a standard professinal radio, it can only turn up to 30 degrees max..and extreme to 45 degree..so wee add a servo streacher..still it can only go up to 120 degree almost..but think about a turret, that can be rotated in 360 degree, with a simple micro servo..and yes with a gun barrel on it that can be elevated..nice..
its too easy to make a servo streacher, with some handy components, but only a few can go through, as it needs a good knowledge in practical electronics..so, if we can rotate a servo in to either direction, it will be simple to make one, and can also used to make more creative things..
here is my idea to make a simple rotating turret, with an elevating gun..and if you are a modeler, that , if you can fix a servo, to a driven mechanism, you can simply add this to your crafts..we can add this to any war ships, PT boats, and land based crafts, including a tank model..
we need only two micro servos for this.. 

all we know, all servos are working on same principle of frequency streaching..and here we do not need to go in to any deep design side..and all servos are designed to rotate within a limit. so, buying a continuous rotating servo is expensive..then we can alter one servo for our needs..

take one micro servo..you can take any micro servo..in to any weight..

remove the all four screws with a micro screw driver..
carefully remove the top cover...take care to avoid spreading the gears all over..

if you feel that you lost the set up of the gear box, draw a sketch in a paper, or take a close up photograph of the servo...
remove all servo gears..

now connect the gear removed servo to a live receiver..then you can see the motor of the servo will rotate in any of the direction, freely...
take a nose plier, and turn the shaft of the potentio meter in to either directions slowly, while the relevent stick, of TX must stay at "0". when the pot reaches a particular area, the motor stops rotating..
remove the nose plier..apply the control stick to either directions..observe the rotation of motor in either direction..and it must stop when you leaves the control stick..if it still rotating slowly..can adjust the trim of TX to stop motor...

now take the main driven gear, that holds the milling for the servo arms..you can see a tag, attached to the under side of the gear once..

cut it off with a sharp heavy duty art knife..and make sure nothing is protuding out...

now..keep the gears away from dust or sand..any..
take the servo in hand..without disturbing the potentiometer..drop some super glue, in a bottle cap, or in to paint cap, and take a tooth pick..
apply thin blob of super glue to the shown part, may be plastic or metal..on either side..take extreme care to avoid the glue spreading in to the carbon pad..

now take a twist drill bit, to the same size of the shaft of the potentio meter..and drill along to the hole, readily having with the driven gear as shown..take care , to avoid over drilling in to out..after drilling make run the bit for several times to make the hole slightly bigger than the shaft size..

after drilling insert the gear to potentio meter shaft, and make sure it is running freely in to both direction, without jamming on the pot shaft...

after making sure, that the driven gear is just free on the shaft of the pot, rearrange the gears back..
and make sure thare are no dust or sand in between the gear teeth..apply a little silicon grease if needed..

put the cover back..please do not try to rotate any servo with fingers in a vilont action..

now take a servo arm like this one..

cut the servo arm, in to a circular ring with a side cutter...
take a washer, that fits to the servo arm gear of the servo..this washer is actually intended to give a slight braking effect to the servo, while we stops it in a position...

place the washer in...
put the servo arm ring in and tighten the servo screw..please do not tight it well..but leave a slight margin between washer and servo body..can tight it later..

now connect back the servo to receiver..
and clamp a crock clip to the servo arm gear as shown..this helps us to notice the rotational direction and speed..
we can rotate the servo in to either directions, and from a very slow speed to a high speed..as per need...

how nice it works...now we got a free rotating servo with us..can do many creative things with it..but here we have to make a working turret with it..will it works..?
see the test video here..

now we got the servo..time to start to make turret.. 

time to make the turret..Friends..all shown ideas are my simplest ideas, and you can add or choose anything apropriate to you..and the shown turrets are not finished, but just painted for testing, so you can fix any turret, shape and sizes..

take some empty ball point pen bodies and tops..

take a soft pen cap, and make sure that fixes with the servo arm ring once..
insert the cap to servo arm..and make sure it is tight..

cut out the excess length of the top..
add a second tube may be anything from a refil to straw..inside of the pen cap..

take a round flange of a servo, and glue the inner tube as shown..

insert the glued part, in to the cap..and make sure it is simply a little tight, but not jamming..it must rotate freely within the cap..

glue a strip of foam board as shown on servo flange..

attach a piece of foam board as shown..these pieces of foam board acts as a stopper of the turret at 360 degree..

make a turret according to your design..here is a simple one completed with foam board..

can make in to any design and any type..

and paint it with your needed colors..
time to check..