HEAVY WEATHER OPERATIONS
By Don Spielberger of Loyalhanna Dockyard
During a recent e-mail exchange with the editor of Model Ship Journal the topic of future articles was discussed. One of the suggested topics was that of rough weather operations of our radio controlled models. Instantly, I agreed to write an article on this subject, as it is near and dear to my heart. The reason for this is simple. The pond my club (Buffalo Model Powerboat Club) normally runs on is very open to the elements and usually provides a challenging mix of wind and current. If a model is not properly prepared for this, there is a good chance that it wonít return home. Even with proper preparation we have had our share of sinkings, but these are usually due to a collision with another model or weather too severe for any model. After surviving numerous rough weather days with reasonable success, I have a few helpful hints and tips to share. That will be the subject of this chapter.
First, letís look at what can be done to prevent water entry into the hull. The critical areas to check are the rudder and prop tubes. Because these tubes actually pierce the hull below the water line, they are the most prone to allow water entry. A simple test will confirm the watertight integrity of these components. Start the test by floating your model (fully loaded to the waterline) for a few hours. If all is OK, there should be no more than a few drops of water in the hull (ideally, none). Any more than a few drops should be investigated. The best way to do this is to dry the inside of the hull with a paper towel and put it back in the water. This time, using a flashlight, very carefully look for the water as it leaks in. The three most likely areas for a leak to occur are between the shaft and tube, between the tube and hull, or a stress crack in the hull near the tube. Once the leak has been discovered, it must be sealed up. Re-lubricating the shaft will usually solve the first situation while the latter two can be solved with the appropriate glue. If you are having trouble tracking down the source of the leak, you may need to try an old trick. Once again, dry the inside of the hull and then dust it with baking soda or talcum power. Place the hull back in the water and use the flashlight to look for the leak. The trail the water will leave in the powder should lead you back to the source of the leak. Once this test is complete and any leaks are sealed up, a dynamic test should be conducted. Place your model back in the water and take it out for a 30-minute run. Bring the model back to shore every 10 minutes or so and check for water. It is not unusual for this test to produce a leak when the float test did not. Again, the first places to suspect are the rudder and prop tubes. When in motion, the bearing surfaces of the prop and rudder tubes may not seal as well as they did in the float test, which could lead to a leak. If this is the case, it may be necessary to switch to a thicker lubricant (either a heavier oil or light grease). I usually start out using light machine oil on my rudderposts and normal motor oil on my prop shafts. As these items wear, I can then change to something with more body such as gear oil or light grease. There will come a time when even the light grease does not seal anymore. When this happens, it is time to resurface or replace the tubes. There are a number of other ways that water could have entered the hull during the dynamic test and these needed to be checked into as well. Check to make sure that the coaming, which locates and waterproofs your removable structures, is intact and watertight. After all, you donít want any water that is on your deck to find its way underneath your cabins and into the hull. Also, since we are talking about water on the deck, make sure your scuppers and wash ports are clear and functioning properly. You need water to be able to wash off the deck as quickly as possible. Another potential source of leakage is the anchor chain entrance to the hull. Make sure this is completely sealed as a lot of water can be pushed through a small opening when the hull is moving. The joint between the deck and the hull should also be carefully examined for leaks. This is extremely important and yet in no way as easy as it sounds. Every inch of this seam deserves careful inspection under a strong light. Even this is no guarantee against leakage. I once had a tug model that would leak, but only under full speed forward conditions. Everything I have mentioned here was carefully checked out, including the deck/hull seam. Another test run produced the same results, a leak only at full speed. The tug would float in the water for days without taking on a drop. Normal cruising speeds and reverse running were also completely dry, but full forward yielded a leak every time. This drove me crazy and I was determined to figure it out. One night, out of desperation, I decided to float the tug in the bathtub with a lit flashlight inside the hull. I then put the cabin in place and turned the lights off. At first there was nothing unusual, so I started to run the motor. Still nothing, that is, until I reached full speed. At full speed there was light from the flashlight leaking through a small portion of the hull/deck seam. After careful study, it was determined that the motor torque at full speed flexed the hull enough to open the seam and admit water. Anything less than full speed and the hull did not flex enough to open the seam. Problem solved, but it did take a great deal of effort.
Now that your model has been checked out and leak proofed as thoroughly as possible, letís look at how to operate your model in heavy weather. There are many conditions that you, as skipper of your craft, can control, which will enhance its chances of surviving. The first item to look at is your drive system. Is it reliable? Your model can suddenly be in a world of trouble if it loses propulsion while enduring wind and wave. Check to make sure mounting bolts are tight, the electrical connections sound and the shaft properly lubricated. OK, so now you are sure it is reliable, but does it have enough power to make headway into the wind and current? I have seen dozens of models that work wonderfully in calm weather only to find they canít make any forward progress into a wind. When the builder is asked why he didnít use a larger motor, the answer is usually ďit would make the boat too fastĒ. Well folks, that is why we have speed controls. Just because you have ďtoo muchĒ power does not mean you have to use it. It is good practice to have a little extra power in reserve for emergencies. Once you are confident that you have enough power to drive your model, it is time to think about the batteries. Since you are running in weather that forces you to use more power, you will drain the batteries faster than usual. Therefore, it would be foolhardy to head out into such bad weather without fully charged batteries. OK, by now you are thinking ďI have the drive system and batteries ready to go, what else could there be?Ē Well, there is at least one other factor to consider and that is the position of your receiver antenna. All of the motor and battery power in the world wonít do any good if your ship canít receive the signal from the transmitter. The ideal position is stretched out to its full length and perpendicular to the waterline with as much above the waterline as possible. If you can position any or all of the antenna above deck level it is even better. Good hiding places are the funnel and superstructure. There are also many doníts with respect to antenna placement. Some of them are: donít coil up any excess antenna length as this diminishes the range; donít run the antenna near any motors no matter how small; donít add to or shorten the length of the supplied antenna; and finally, keep as far away from power wiring as possible.
Inevitably, even with the best preparation, sooner or later water will get into the hull. Therefore, there are certain steps that should be taken to minimize the effect of said water. First and foremost would be to waterproof all surfaces of all wood parts. Not only will this protect the model from eventual rot but it will also prevent potential warping (which could pop a seam and lead to other problems). Once this is taken care of, your focus should shift to that of the electronic and electro-mechanical items in your model. These components are notorious for their dislike of water! It is a good practice to mount the receiver high up in the hull. Usually, the higher the better. This helps in two ways. First, it makes the routing of the antenna (which was discussed earlier) easier and second, it keeps the receiver away from any water that might find a way into the hull. A favorite mounting place of mine for the receiver is upside down underneath the main deck. It is almost impossible to get wet there. These same recommendations apply to the speed control. The only additional concern here is the heat generated by the speed control during operation. Consider the heat developed and its effect on surrounding components when selecting a location for the speed control. The batteries and motor provide a different set of problems. Again, it would be ideal to mount them up high in the hull. Unfortunately, this is not possible in most circumstances due mainly to their weight and consequent effect on balance and stability. Since these items must be kept low in the hull (which is where any water present will collect), they will have to be waterproofed as best as possible. There are a number of things that can be done for the battery. First, all soldered connections and exposed cell ends can be covered with a coat of clear lacquer to prevent shorting and corrosion. The battery can then be covered in heat shrink plastic tubing for further protection. Heat shrink tubing can be purchased in sizes large enough to contain most of the various types of batteries we use. While this may not be completely waterproof, it is definitely water and wear resistant. To make your battery pack truly waterproof, the battery can be dipped in the liquid plastic used to make the handgrips on tools. This material can usually be found in well-stocked hardware stores and home centers. Due to its function and construction, there is little that can be done to waterproof the motor, shy of building a watertight compartment for it. In most cases it is acceptable to just waterproof the terminals with heat shrink tubing and clear lacquer and just clean and maintain the motor often. One final component that should be considered is the transmitter. You might ask ďwhy the transmitter?Ē Well, there are at least two good reasons. If you are running in rough weather, it is entirely possible that it is windy or raining (or both). If it is raining, the problem is obvious and the transmitter should be kept inside a plastic bag (even during operation). Wind, however, presents a different problem. I donít know how many times I have seen somebody set their boat and transmitter down on a card table (or picnic bench) pondside to take care of their model. A moment later, while their attention is on the model, the wind gusts and knocks the transmitter off the table. Sometimes the transmitter will survive, but most times they tend to land face down (must be some variant of Murphyís law) on the sticks, smashing the gimbals. The goal of this article is to keep the entire system that is your model safe and sound so please donít forget your transmitter.
By this point we know how to prevent, or at least minimize, the entry of water into the hull. We have also discussed how to help the critical components survive any water that may sneak in. Now it is time to consider the fact that even with all of these preparations something may go horribly wrong and your model may sink. If you have ever seen a model sink, you know there is a period of time from the moment you realize that you have a problem to the moment that the hull slips completely under water. The longer this period of time, the greater the chance of rescuing the model. The best way to extend this time is to build floatation pockets into the hull. There are a number of ways to do this and one of the best is to build airtight chambers into unused cavities in the hull. It can be a great deal of work to build such a chamber and make sure that it is airtight so an alternative may want to be considered. An easier, but still very effective, method is to pack foam (or ping pong balls) into the unused spaces. While this may not provide enough floatation to keep the hull from sinking, it will buy you additional time to attempt a rescue.
Even with your best preventative efforts, you may still lose your pride and joy. In this case, the primary concern must now shift to recovery. The single most important element to a successful recovery is knowing exactly where your model went down. Over the years I have seen many very inventive ways of marking the location of a downed model. One of the best was by a fellow club member. He owned a small (24Ē) harbor tug which had a fishing bobber tied to 20í of string stored in the funnel. One end of the string was connected to the bobber and the other end was tied off at the inside of the base of the funnel. The cabin/funnel was then connected with a length of string to a very solid point in the hull. The theory was that if the model went down, the bobber would float free of the funnel and rise to the surface. The diver could then follow the string to the sunken model. Since that time, I have seen many variations of that idea. Luckily, none of these methods have been put to the test yet, but there is no reason that they should not work. Without such an onboard self-marking scheme, you will be forced to use a shore based method. A method that has worked well for our local club is based upon spotters carefully sighting where the model went down. The idea is to have the spotter line up with some landmark on the far shore as the ship is going under. Once lined up, the spotter has to determine how far out the point of sinking is. The spotter should then hold his position and sight line while the rescue attempt is made. If for some reason the spotter canít stay, or the rescue has to be made at a later time, then the spotters position on the shore should be marked in some way. A large stone or stick driven into the ground works well. Due to the inherent guessing of distance required by this method, it would be advantageous to have more than one spotter. Actually, the more the better, as their sight lines will be from different angles and would cross each other at the point of sinking. Even with extra spotters to increase the accuracy of the spot, it is only a starting point for the search. Even in a still pond most models do not go straight down. Many ponds (such as ours in Buffalo, N.Y.) have a current, which can drag the model as it is sinking. We once recovered a model 15í from a very accurate spot at which it went under. Obviously the currents were working overtime that day, as the pond was only 12í deep in that area. Remember, even the best marking efforts donít guarantee a recovery, but you should at least give it a try as the gods may be smiling on you that day. Hey, you never know.
If you are skilled (or lucky) enough to recover your masterpiece, your next task is to assess the damage. The first thing to do is to get the water out of the hull. Dump out as much as possible and then remove the rest with sponges, turkey basters, paper towels or whatever method you like. Once all of the standing water has been taken care of, remove as many of the electrical components as possible. Set the hull and superstructure aside to air out while working on the electronics. Next open up the receiver, servo(s), speed control and any other electronics that can be opened. Dump out any standing water and then dry off with canned air (available at office supply stores for cleaning computer keyboards). Ideally, all of these efforts should be conducted pond side immediately after recovery. This provides the best chance for the electronics to survive. If this is not possible pond side, then it should be done as soon as you return home. After everything has been opened up and allowed to dry out for a few days in a well-ventilated area, it is time to check things out. Check the hull over for any warping, twisting or paint peeling that may have been caused by the dunking. If anything is found, repair it immediately. Also check your steering linkages and drive line for rust and corrosion. This would be a good time to lubricate all of these components once more. All electrical components should also be checked for corrosion, and if any is found, it should be cleaned up before the case is replaced. If you were operating in fresh water, there is a good chance that your electronics will survive. A drowning in salt water greatly reduces these chances but does not eliminate them. Once the electronics have been put back together and tested to your satisfaction, they can be returned to the model.
If all else fails, I have been told that sacrifices to the Gods of the deep are effective in the prevention of a sinking. As an alternative, you may want to name your model after many of the ancient good luck charms. Hey, what have you got to lose (other than your ship).
I hope that this installment has at least provided some ideas and viewpoints that will help you prepare your ship for the sometimes-unfriendly conditions it must operate in. I am sure there are a great many more tricks of the trade that have not been presented here due to space limitations and I would love to hear what your favorites are. Since we are planning a series of technical and helpful building Books, we appreciate input from readers as to the content they would like to read. Hopefully, the thoughts and comments presented here have started the gears turning in your head. Now that they are turning, you will be surprised at how many new ideas present themselves to you. As always your thoughts and comments about this chapter are welcome and encouraged. Feel free to contact the publisher or myself (firstname.lastname@example.org).