How to pick the right troll motor:

Troll motors are a lot like outboards; there's not one choice that is always the right choice. We have fewer brands to choose from, but models within the brands are many and widely varied not only in power, rated as pounds of thrust, but in voltage. It makes the choice a bit mind boggling, and everyone has their opinions. Here are mine, as unbiased as I can be:

The 15's and 17's really do not need anything more than a 12 volt system. They are produced with up to 55 lb thrust these days and that's pretty good really. I know everyone imagines there will be that time with the strong current and stiff wind they have to beat, but I'm more a go with the flow kind of fisherman. I use the big engine to position the boat upstream or upwind, then use the troller to guide the boat as it's pushed by the elements. My battery lasts longer that way, and so does the troll motor. Do I catch more fish? I don't really know, but it's not about quantity to me, but more about the experience and sharing it with someone I care about. Now a tournament fisherman may have other needs, and a 24 bolt or even 36 volt system may be right for him, but then he's not likely to be fishing from a 15 or 17 these days.

The 18's and up really ought to have a 24 volt system, and in some of the bigger models such as the 230BR or 246BR, maybe even a 36 volt system. They start out around 70 lb thrust and go up to just over 100 lb. I've used the 70lb motor on a 210BR in nasty conditions and found it to be fine. Would more thrust have been better? Rarely, but I can always turn down the thrust just as I can pull back the throttle on the big engine. I've told many people I've never had a boat with too much power, on either end. I know how to adjust it. Remember though that just as there is a price to pay for more engine power in cost, weight, and fuel, there's a price to pay in troll motor power. One of the major considerations is that the higher the voltage, the more batteries they require, and those batteries are heavy and take up valuable space. Consider all this before making your choice.

After the thrust and voltage question we have the shaft length question. This one isn't as difficult as the others but there are some considerations. If you choose a hand control model the shaft should be longer to allow easy access to the handle while standing or sitting. Standing of course requiring a higher handle than sitting. When I go with a tiller control I go with the longest shaft available for that thrust; usually at least 52" and maybe as long as 64". The boat height above the water obviously comes into play as well. The 15's and 17's, as well as the bay series, have a bow that doesn't sit terribly high above the water at rest. This is by design so they can be more easily controlled in a stiff wind that is likely to be encountered in open bays. Remember the higher and deeper boats have a larger 'sail' area for the wind to push. They are harder to control and require more thrust than the models designed around troll motor use such as the bays.

To get an idea of the shaft length you need as a minimum measure the distance from the top of the bow, or the deck, down to the water line. Remember the water line always varies with weight placement, and then add at least eight inches or so. If they prop gets too close to the water line it will grab air and churn so you want some play there. Then consider the method of operation. For instance with a foot control motor I can go shorter on the shaft length than with a tiller because I don't need to reach it. This goes for the remote control models as well. Shorter shaft allows you to fish over the troll motor easier, especially important for the fly fishermen or when throwing a cast net.

We also have the remote control models that have gained so much popularity. I’ve tried these and they do have some features that are very nice. For instance the virtual anchor. On the remote the operator simply clicks the “Anchor” button, and the troll motor holds the boat where it is. That relieves the fisherman of the chore and allows you to work that area without paying so much attention to running the motor.

Some models take it a step further and include a remote deploy and retrieve button. Imagine deploying the motor, navigating the boat, anchoring, then retrieving the motor, while never leaving the rear seat. Guides have got to love this one, not to mention the grandpa taking the kids fishing.

This may not give you an exact answer for shaft length and power requirements but it should give you an idea of where to start in the thought process. What is right for one may not be right for another, like most personal decisions. I hope this helps.

Steering effort and jack plates:

Now and then we have a case where a new owner of a bay boat has a problem with the steering. This is almost always caused by the torque created by the propeller which is neither a boat nor a steering system problem, but because it is so often misunderstood I thought it a good idea to explain how and why this is happening and what can be done to help cure the problem.

First I’d like to comment that steering problems where the steering effort exceeds expectations have been growing steadily in the last few years. In part this is attributable to the consumers themselves. If you think of it, most of them have never driven a vehicle of any kind without power steering. The truck or car they drove to the dealership had power steering and usually every other vehicle in their lives. Then they drive a boat which has of course an outboard motor that can operate at different speeds, trim angles, engine heights, and can use an all but infinite number of varying props. All of these variable can have an effect on steering torque, and the only method of correcting that steering torque is usually the torque tab on the engine’s anti ventilation plate.

I’ve told people for many years there is only one speed, trim angle, engine height, etc where the torque tab can neutralize the steering effort, if any, and all other engine speeds and trim angles will result in some steering torque. The degree of that torque varies tremendously depending on the application going from barely perceptible to impossible to overcome. It is important to remember that all of this torque is created by the propeller rotating through the water. Not the engine, the steering system itself, or least of all the boat. The boat is nothing more than an inert piece of material to which the other parts are attached in this situation.

Notice I said only one set of variables can be neutralized by the torque tab, if any. There are cases, and that number is growing, where the tab simply cannot do that job. Why? Look at the typical tab on let’s say a 50 hp engine. Then compare the size of that tab to the one on a 250 hp engine. Even though there is five times as much power spinning a much larger propeller the tabs are nearly identical in size. If it’s just right on the 50 hp, it’s way too small on the 250 hp.

Another cause of increased steering problems caused by prop torque is the props themselves. In the last ten years I’ve noticed a trend to larger diameter props. Often this results in more efficiency especially at mid range speeds, but it also contributes to the steering torque transmitted from spinning it through the water. This increased prop torque has not been met with increased torque correction in most cases, and I fault the engine builders for that oversight. The technology is there and has been for many years to do so. Going way back to the mid to late 70’s when bass boats were very popular and faster speeds were needed to get to the good fishing spot first the owners and dealers started experimenting with elevated engine heights via jack plates. This resulted in the same increased prop torque we have now as a result of taking the torque tab out of the flow of water.

So why does this elevated position result in more prop torque? It’s really simple physics. One of Newton’s laws regards the natural equal and opposite reaction with regard to a moving object. The prop spins to the right, twisting the engine to the left, resulting in a pull to the right at the steering wheel. When the prop is completely immersed in the water the blade on top partially counters the blade on the bottom, but not quite because it runs behind the engine’s gear case where the water flow is disturbed and the blade doesn’t get quite the bite as the blade on the bottom in undisturbed water.  As the prop is raised the blade on top begins to surface dramatically reducing the drag on that blade and its ability to counter the twisting force of the blade on the bottom. At the same time the torque tab is clearing the flow of water coming from under the boat and it eventually has no effect at all in countering steering torque.

The cure for this is involves is the curved skeg found on the Yamaha SHO 200hp through 250hp and the Evinrude G2 series engines. I first saw this used on the Evinrude Rude Ram in 2000 on what they called their Lightning Gearcase. These high speed gear cases not only include this very effective torque correction in the skeg, but also utilize a low water pickup for the elevated running positions. This is to keep a constant water flow going to the water pump to cool the engine.

After market companies such as TH Marine and Bob’s Machine also offer an add on wedge to be attached to the lower skeg of engines not built this way. These simple and inexpensive devices go back to the early bass boat days and are still inexpensive and effective today. If you have an engine mounted on a jack plate allowing the engine to be raised on the transom, whether it be fixed or hydraulic, I highly recommend these devices if you do not have a SHO engine on the boat.  

Info at this link. http://www.thmarine.com/products/Outboard-Performance/Outboard-Torque-Tabs  and pictures/ pricing at this link http://www.amazon.com/T-H-Marine-Torque-Tab/dp/B0000AXV99/ref=sr_1_fkmr0_1?ie=UTF8&qid=1410549736&sr=8-1-fkmr0&keywords=the+marine+outboard+torque+tab

Good news is on the horizon with regard to engine porp torque and hard steering. The same torque correction found in the SHO engines is also incorporated again in the new Evinrude G2 engines from 200 hp through 300 hp, and it is standard in all shaft lengths. The SHO engines are currently only available with this technology in the 20” shafts.

Another problem with steering torque is the confusion floating around hydraulic steering. People often confuse hydraulic for power steering. While hydraulic steering can offer less resistance to steering effort than mechanical it is done through the number of steering wheel turns required to move the engine the same distance as compared to the mechanical system. For instance the typical mechanical set up requires around 2.7 turns to go from hard right to hard left. The average hydraulic system requires around 5 turns to do the same thing, and some of them as many as 7 turns. Like changing gears on a winch,  more turns equals less effort to turn the wheel. But even though hydraulic may be easier than mechanical it does nothing to remove the torque from the prop, it only serves to help the driver overcome that torque. As the torque increases from one or more of the aforementioned variables it comes to a point where the operator of the boat is stressed to steer and often times they now assume something is wrong with the steering, or the boat.

Power assist steering can help overcome this complaint. Remember it is an option on most boats equipped with hydraulic steering but it should be offered before the complaint whenever possible. It is up to the dealer to anticipate this need depending on the set up being sold. I personally don’t like this solution since it does not relieve the pressure created by prop torque, it only overcomes it. In extreme cases such as an elevated running height where the top of the prop as well as the torque tab are out of the water flow the torque can be tremendous along with very high hydraulic pressures inside the steering cylinder, hoses, and the helm. If something breaks in the steering it can result in catastrophic results including loss of property and life. Because of this I always recommend that steps be taken to reduce the torque before steps are taken to overcome it.

I hope this dissertation is helpful and can help us all to keep the new owners happy with their Key West Boats. Remember this is not an issue isolated to Key West Boats in any way, but part of high speed recreational boating for many years.  While this article was written primarily for bay boats equipped with hydraulic jack plates many of the facts covered here with regard to prop torque and exaggerated steering effort apply to many other applications as well.

Thanks

Tom Marlowe

Key West Boats 

How can Stainless Steel rust?

The stainless rusting issue pops up now and then and the accusation is often made that cheap material is being used in a money saving effort. Even though that seems to be a logical explanation it’s not really true. When it comes to marine parts made of stainless I’ve never really seen a “cheap” alternative from any of the suppliers.

 Speaking of suppliers, there is a relatively small selection of suppliers of hardware dedicated to boat building, and from that group an even smaller collection of them are what we call preferred suppliers. Most of the major builders of boats in the US use the same group of preferred suppliers and do so as a buying group to better control pricing. Because of that the quality of the cleat, or the hinge, or latch that goes on a Whaler for instance is the same as the one that goes on a Key West. They come from the same source, in the same box, and often on the same shipper, landing in a warehouse where they are distributed to the various builders.

Bottom line, if the material is rusting on one brand and not on another, there’s another explanation rather than quality or cost. While that is a fact having the consumer with rusted material to understand that is the tough part. Since I am obviously susceptible to bias in an explanation I go to the internet for help. In the search box I enter, “How can SS rust”. The following header pops up with over a million results. The first dozen or so are very good explanations. One of the best technical explanations is the second link below.

https://www.google.com/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=how%20can%20stainless%20steel%20rust

http://www.sperkoengineering.com/html/Rust.pdf

While this PDF is directed at industrial applications the chemical properties of stainless apply across the board. Of particular interest is the ferrous material that can be introduced to the surface of the stainless material starting the rust process. How can that apply to the hardware on a boat?

In the water used to wash the boat, surprisingly. Most of us have seen the rust stained sidewalk or driveway where the irrigation water splashes over from the grass. The same iron in that water can end up on the hardware on a boat causing it to rust. In cases where the water has ferrous material suspended it would b better to wash the boat with salt water instead. I’ve seen cases where every piece of stainless on the boat was rusted and it was traced back to the well water used to rinse the boat diligently after each use. That customer was convinced that we used cheap material to save money. Sometimes it’s just the water.

  A discussion forum for Bradenton resulted in the post at this link. http://www.city-data.com/forum/sarasota-bradenton-venice-area/339596-city-water-vs-well-water-2.html and the latest 2014 water quality report for city water listed salt and minerals as contaminants.

How to combat that is the question. Each boat owner’s packet comes with a stainless care instructional in the owner’s bag. I’d also suggest a towel dry concentrating on the hardware, as well as some sort of anti corrosion treatment. To remove the rust I suggest a mild abrasive stainless polish such as AERO disinfectant cream cleanser available from Aero Chemical Co., Atlanta Ga. 

Slow Fill on EPA regulated fuel systems: 

EPA regulated fuel tanks and the supporting parts are one of the most misunderstood yet simplest parts of boats built in recent years. Because of that techs in the marine industry spend lots of time diagnosing problems or complaints, and often more time than is necessary. I will try to help explain the way they work and what to do when they do not function as we expect them.

First the most common complaint is slow to fill. The most common cause of this complaint is the tank is full by design, but it will take more fuel if the operator is persistent enough. In fact the bigger tanks may take another 10 gallons or so after the tank is actually full. Of course this doesn’t make sense, until you understand what is going on. So let’s cover ullage space first.

Ullage is literally an air space maintained in the tank to allow for expansion during a normal heating and cooling cycle of a 24 hour period. This air space is big enough to contain the fuel without it being pushed into the vent line, which prevents the fuel from spilling overboard and contaminating the environment. In some systems there is a charcoal canister in the vent line which could be rendered inoperable when fuel enters the canister, and it can even become a plug in the vent line which would make fueling difficult at any time.

This brings us to the next issue where ullage space is concerned. Most tank builders, or maybe we should say fuel level sender builders, do not allow for that air space in the design of the fuel level sender. Most senders are a straight shaft mounted vertically from the top of the tank. On that shaft is a float which activates sensors in the shaft which in turn send an ohms reading to the fuel gauge. This ohms reading is interpreted by the gauge as a fuel level. Introduce the ullage space and the float can no longer reach the top of the shaft, so the full tank will sometimes result in a ¾ or so reading on the gauge. Seeing that on the gauge encourages the operator to keep on filling. Unfortunately modified senders to allow for ullage are not commonly in use, but they are coming.

Now let’s move on to physical problems that could cause the slow fill situation even when the tank is not already full. The most common physical cause is a venting problem.  A pinched or kinked vent line can be the cause. Test for that removing the vent line at the tank and blowing through it. It should allow air to pass through that line with little effort. Some vent lines will have valves or canisters, but still should allow an easy flow of air since that is what happens during filling. Keep in mind some of the vents are in the fill assembly so best to remove the fill cap to be sure the vent outlet is open.

The least common cause of slow fill is the fill line itself. This is a big and tough hose that is hard to kink or crush so that cause is extremely uncommon, but there have been some cases in older hoses where the inside lining of the hose has bubbled out effectively blocking the incoming fuel. Again, this is extremely rare but when all else is right, remember this one.

And another surprise the EPA tanks threw our way; some of the fill systems will only accept fuel at the rate it comes out of the pump. So the dock caddies, jugs, whatever present a challenge of filling too slow. There are some special funnels out there in the aftermarket designed to overcome this challenge.

In summary, EPA regulations have led to a more complex system with mysterious connections, but the fill process is very much the same as it’s always been. When fuel comes in, the air needs to flow out. Keep this in mind and most of the mystery is irrelevant.