Servo question

This probably seem a silly question to those who know the answer…

I have noticed a couple of Footies with deck mounted servos; are the top of all servos waterproof or is there a special kind ??


They are standard servos that they try to waterproof as much as possible. Top mounting them means they mainly have to withstand splashes at the shaft.

Boats using these are mainly all foam construction and a few can be seen at Sand Point MSC in Titusville (look for Shark at and Sunday Sloopers.

There will be some showing up in Tanglewood on Jan 17th for FFF II.

I have used standard cheap Hitec HS-55 servos on deck for rudder control. I put a blob of Vaselene on the shaft before fitting the servo arm to act as a sealant and use silicone sealant around the servo body/deck junction. I think it’s a good idea to avoid using a servo with metal gears or a ballrace for obvious reasons. As Frank commented the worst they should see on the rear deck is a splash of water.

I prefer to keep my sail servo below deck so haven’t had to worry about waterproofing that more powerful expensive servo.


I to sometimes deck mount servos and when i do i use a heavy silicone grease to seal the shaft - on all my servos i take the base off and smear a film of Holts “No-Crode” its a battery grease that stops water getting in and prevents corrosion to the electronics.

Sadly this product is no longer made so no you cant have my last tube but there must be some other battery terminal grease out there?

Thank you gentlemen

I think you’d use dielectric grease in stead of the battery grease, but I remember when the old man used it on the old Chevy… :smiley:

The new thing to protect the insides of your servos is to either coat the innards or fill the servo with CorrosionX, which is (or was) sold in hobby stores as “The Stuph.”

I’m suprised that there isn’t some company out there making silicone rubber servo covers, like the silicone rubber receiver covers I have, which didn’t work… :rolleyes:

Some Lowes (possibly not all) carry a product in their electrical department from 3M called “Scotchkote Electrical Coating” (item 43906). It is basically a type of liquid electrical tape, and comes in a 4oz. tin can with a screw top, mounted on a hanging peg-hookable card wrapped with clear shrink plastic. Depending on the display layout, this may be set out on a peg hook, or displayed on a shelf or bin. The card is yellow at the top (1"), and fades to red for the remaining 5" of the card, and the can contained within is red. This description is provided in case the Lowes near you suffers from the typical “lack of salespeople when you need to find something”, like everywhere else. This product is highly recommended over “tool dip” for sealing R/C gear, by the R/C battleship modelers, who pelt their models with “BB” cannon fire to the point of sinking (they should know about waterproofing!). You’ll still have to put a dab of Vaseline under the servo horn to complete the sealing job.

Good luck,
Bill Nielsen
Oakland Park, FL USA

Moth, here in the US there is a product that I picked up at an r/c trade show called “Aeroplate”. In their demonstration they ran an electric train under water in an aquarium. They recommend that you soak the electronics in this solution to waterproof them. Since I started to use this product I haven’t had any problems with my r/c gear failing when exposed to water. I do not carry my servos above deck though. If Aeroplate is still available the company that makes it is called Aerotrend, is the web site address.

Neil, that’s an interesting product.

I’ve always been soaking my circut boards in melted candle wax; but this stuff here, looks like it make the job a whole lot easier.


I’m one of the “keep the servos exposed” boats you you may have seen - I copied this from GaryS and have never had a hint of a problem, and don’t expect to. I do use plastic geared, plastic bushed cheap servos which are hardly going to mind a little water lubrication.
FWIW I have asked Roger Stollery about his use of exposed servos - he uses a felt or foam disc under the servo arm and soaks it in grease - and has never had a failure.

In used to work for a company who “tropicalised” their circuit boards by dipping them into polyurethane varnish - effectively sealing them - might be easier than candle wax:D


Darling you light the candles i’ll servo the wine

Roger uses felt disks greased with Teflon grease available from Halfords. I have sailed with Roger quite a bit and know that he has had no gear failures. However Roger’s boats have lots of freeboard - particularly the Ant - so may not always be typical. Also we need to think about using the boats at sea water venues - Hove and Clevedon for instance - where salt and metal gears would not mix.

I have found that the easiest way to cut the disks is to use a hollow punch for the circular shape and a standard hole punch for the centre.

Happy new year


Hello Charles – I was always taught to be cautious - I’ve been using TowerPro MG995’s for my sail servo’s on 507’s and my V12 at Clevedon for the past year and thankfully no failures - but then I am meticulous about weatherising them.

I think it’s fair to say that skippers should be taking ALL necessary precautions. It doesn’t really matter if its salt or fresh I still put batteries and receivers in balloons and silicone the neck and then zip tie it

May be I’m going a bit over kill but I have had a couple of near misses and with 2,4GHz Rx costing £60ish my cautious attitude has been beneficial

I found this review of the MG995 servo:

and this:

A digital servo in a footy seems a little overkill.

Gumstix to you sir!:devil3::devil3::graduate::graduate:

Tomohawk, thanks for the links - not that i fly planes but i would not have put them in the air however i do think they are ok for land and water - I must admit they are very low cost - got 4 of them for £20 inc postage from HK.

Each to his own - im ok with mine

Angus ~ I know this is your pet word at the moment and that these are used in UAV’s and robotic fish and … oh now i get it … tow the footy round the course… well thats one way to fend off Trevor’ Minstralette

Of course the best means of keeping your r/c gear waterproof is to mount it inside your waterproof boat. If as much attention were paid to preventing leaks as has been paid to different methods of waterproofing a servo here then waterproofing a servo wouldn’t really be necessary.

Carrying your servos on deck makes them difficult to replace if they should fail (as well as subjecting them to the elements which will make them more likely to fail). Plucking them out of a hole and mounting a new one in place along with making the connections takes a fair amount of time. Here in the US we allow only a five minute hold between races to effect repairs. To be competitive you have to be able to make changes within those five minutes, in the rain, cold, and wind.

A removable r/c mounting is what I use, taking an identical backup along for emergencies. Having a removable tray makes swapping out your r/c quick and painless. No messing with small screws when your fingers are cold. No switching the suspect servo and having the system still not work. If you swap out everything and replace it all with an alternate then you can keep your head in the race and figure out what went wrong later when it is convenient to do so.

So, I mount the receiver and servos are on a removable, lightweight, balsa/fiberglass sandwich tray. Easy disconnects for the mainsheet and rudder linkage are important to consider as these will directly impact on how fast you can swap trays. For the winch attachment on my Tanto, the single mainsheet with a loop on the end passes through a hole in the end of the winch arm and then over a hook mounted on the stern. To disconnect and reconnect just requires lifting the loop or replacing the loop on the hook. The hook is bent from 1/32nd, 220# test, s.s. leader wire. The hook is not “open”, it folds back on itself so that the lead in to the curved part of the hook touches the return from the curved part. This keeps the loop from slipping off on it’s own but doesn’t impede taking the mainsheet on or off the hook.

For the rudder I use a “whipstaff” system (inspiration from Angus). The tiller arm from the servo has a downward aimed pin that engages a tiller arm from the rudder post that has a slot the same width as the pin. This system provides more sensitive steering for small course adjustments with the greater throw coming into play at the extremes of transmitter stick movement. This is opposite from the standard push rod system employed by most model yachts. In addition the pin/slot system allows the linkage to be quickly disconnected just by lifting the r/c tray.

All told, taking off my hatch cover seems to take longer than swapping out the r/c tray. Any system you use should allow you to change faulty parts within five minutes. I am sure that the average skipper that hasn’t had any problems yet thinks that this is ample time to effect repairs. I would encourage everyone to test their ability to change out and replace a servo in five minutes outdoors on a windy day with the boat fully rigged. Doing this when not in a racing situation is good practice for when you may need to do it under pressure. I sure you’ll be surprised at how little time five minutes really is.


I think you may have missed the point with the deck mounted servos. I think it was Roger Stollery here in the U.K. introduced the idea, and the general layout is illustrated on the plans for his BUG boats. I’d post a copy, but I may be infringing copyright rules ! !

I don’t know Roger’s reason for using this system, but when it has been adopted by others over here it has been primarily to allow for the rapid changing of servos in the event of a failure. The servos themselves are fitted to a small sub-deck about 2" square. The main deck has a 2" square recess and the servos are just dropped in and taped in place. The idea is that you have a spare servo tray which makes the interchange quick and easy. Roger actually mounts the radio and batteries in the same cassette, but others mount the batteries and radio on the hull floor for ease of balance adjustment. Roger, being Roger, gets it all balanced in the first place so doesn’t have this need :lol:

Other advantages seem to be that there is no need for potentially leaky sheet holes in the deck, and the linkage and access to a transom mounted rudder is much simpler. In fact, access to all rigging is easier.



FF, different strokes for different folks. Swede Johnson, one of the more prolific model yacht designers in the US, carries his r/c gear on his hatch cover. He also has plastic canopy over the cover to keep the sheet lines from fouling on the exposed equipment. He swears by the system but I like a clean deck and the electronics as low as practical inside the boat to maximize righting moment.

My sheet exits the transom. I have sailed my Footies in some of the roughest water, waves I wouldn’t put my M boat in, and they have stayed dry inside. Thats why, in the first paragraph in my previous post, I emphasized that everyone’s first concern should be making sure they have a waterproof hull. Putting your servos inside then becomes a natural extension. If you don’t mind having a wet interior then by all means put your servos anywhere you like and make sure they are waterproof.