BanoDyne - Engine Mounting Photos Optimax Mercury

Different props have different effects on steering weight. Even with hydraulic steering, you should balance out the steering pull using a tab or a torque tamer on the skeg depending on the speeds you run. I don't like the idea of a motor constantly having a force back on the steering that isn't necessary, even if you can steer OK over it.

Obviously a prop creates forwards thrust. But they aren't perfect devices, they also create some sideways forces. That is why counter rotation is available for multiple engine applications. For singles, you have the tab or tamer/special skeg. Doing it in the skeg is fine because you don't need 100% perfect, 80% is fine. So you don't really need to be able to adjust it. It won't hurt if you have 10% too much correction or 20% too little. I guess they tend to aim for too little though as this keeps drag to a minimum and still does enough.

With decent steering systems that have plenty of headroom you can safely go without but it can make a difference in the steering weight.

Early in this tread, there was talk about airguides. I've had dual speedos and run one off the motor and the other off an airguide weedmaster pickup. The motor one is heaps less likely to get blocked at least 10 to 1 better or more. On my new boat, I just T'd off the motor to all three speedos.

I know the brass tube as an equalizer tube. The input must go in the bottom and the output must go out the top. I find they slow the reaction down too much. Somebody I know bragged about how his boat never needed the throttle compensated in the course. Just put on some revs as they pull though the gate and it will hold. We took off the top hose from the tubes, drove the boat until water came out the top and put them back on. Then he got useful speedo readings and found he actually did need to compensate for each pull. No longer did it take all day for the speedos to catch up to a barefooter.

I never did compare a single speedo not having the tube at all to having it full of water. I assume the result is similar, especially if you have a good deep pickup such as off the engine.

My current setup has a T in the back of the boat, one used for in three for out. I just used watering system parts for that.... I ran three hoses from the back to the front. I didn't want any leaks at the front as I didn't want water in the speedos as can happen if there is any leak up there. Also, this gave me some dampening effect by having three hoses even though they are very small diameter. I'm really happy with it. I don't think I would recommend a single hose to the front although it would mostl likely be OK if care was taken to ensure leaks were prevented.

I'm not sure how an airguide performs with a single line and no dampner but I suspect it would be fine, especially off an outboard leg pickup.

If anybody needs a 2025 Airguide in KMH (black with white lettering) or MPH 2025W (white with black lettering), I can help.

 

I agree with all of that except that I think the airguide weedless pickups are about 1000 to 1 more likely to clog than the motor pickup.

I run one airguide off of the motor pickup and the other airguide off of two airguide weedless pickups. The hoses from the pickups lead to a fuel selector valve which can select either pickup for the airguide speedometer. One pick up leads through one of the brass tube equalizer and the other is direct without the brass tube. The one without the equalizer reacts MUCH faster and is the preferred set up in my mind.

The motor pick-up is superior to either of the other set-ups and is the primary source for speed readings for me.

The inboards do not have this option and I believe that is what lead to the lack of demand for the Airguide speedometer and the subsequent demise of the company. I drove a new Malibu Response a few years ago and the lag in the water driven speed system was not acceptable after using my set up. A lot of the inboards have gone to inertial speed which works at the higher slalom speeds but is not satisfactory for slow speed work in a river due to the inherent limitations associated with inertial speeds.

It is my theory that the equalizer tubes primary purpose is to prevent water from making it over the transom and becoming trapped in the lines. Without the tube and with a lot of high speed work, the lines do need to be blown out occasionally.

jim

 

After much study and consideration, I set my boat up with three pick-ups (pitots). I'm in the minority on this, I guess. My two Airguides are set up with the equalizer tubes and airguide pick-ups. My standard Faria speedo is hooked to the shaft pitot. I bought the airguides new and have the directions for them, which I believe state the purpose for the tubes. I keep meaning to go and look at them so I can report on what they say about it. My recollection is that the tubes are intended to keep the speedometer from overreacting to momentary changes in pressure. I used to pull in the slalom course quite a bit and in my experience, which is certainly modest compared to many others on this website, the tendency is to overreact to speedometer changes with too much throttle activity, which just causes driver-induced oscillation of speed control.

Our lake was very shallow this year, which resulted in a lot of weed problems with the pick-ups. I agree that the shaft pitot is less likely to get fouled by weeds, although mine certainly did plug up from time to time this summer. I actually had a single instance where all three pick-ups were plugged during a ski run.

My engine (2006 225 Opti) was set up from the factory with the shaft pitot hose hooked to a digital pick-up in the engine compartment that feeds digital speed information to the Smartcraft Instrument (which I did install). I contacted Mercury and spoke with one of their engineers about whether I could simply "T" the pressure line so that I can get speed readings on both my Faria gauge and on the Smartcraft digital gauge. His response was "absolutely not." He insisted that this would degrade the accuracy of both speedometers. I know that Jim disagreed with this conclusion, because I spoke with Jim about it afterwards.

I have thought through the physics of this and I would tend to agree with Jim. I cannot see why a constant pressure going through the pressure lines would not give an accurate reading whether there is one speedometer or 3. To the extent that pressure is "used up" to move one speedometer diaphram, there is constant pressure added at the pitot end to replace pressure used to move the diaphram. In other words, because the boat is moving, there is a constant supply of pressure and, constant pressure should equal constant reading on the gauges at the designated level for a given pressure.

Having noted the foregoing, I remain glad that I set my system up the way I did for my particular application. There are very weedy areas on our lake and a busy day of skiiing results in a lot of floating weeds. On a lake with few weeds, you might never see a blockage on a shaft pitot. However, on a flowage lake like ours, with shallow, weedy areas at either end, you see the shaft pitot plugged with some regularity. My percentage of shaft pitot blockages this summer was much closer to the 1:10 ratio than 1:1000. Thus, I really need the redundancy of multiple pitots. A final consideration is the issue of a "partially" blocked pitot. You will notice this right away with my set-up because of differential readings on the gauges. With everything coming from a single pitot, you may be misled as to your speed with a partial blockage of a single pitot.

Conclusion? Best set-up probably depends on your specific application. For a weedy lake with busy boat traffic (weeds getting sliced up quite a bit), I'm not sure I would agree that a single, shaft pitot T'd to all speedos is necessarily the best arrangement. If I was on a deeper, less weedy lake I guess I would agree that might be the best way to go. As for the equalizer tubes on the Airguides - I think they are probably good in some respects and not so good in other respects. I actually like the stability provided on the Airguides with the tubes in stalled as intended by the manufacturer. With the third speedo on the panel (the Faria) I can and do benefit from comparing speed information on all three to figure out what is really going on. From what I've heard and read, Airguides' demise is probably unrelated to its sales of boat speedometers. The company made many things besides just boat speedometers. However, I've got to figure that GPS is what would have hurt pressure-based boat speedo sales the most. I'm not necessarily a fan of GPS speedos for waterskiing applications myself (particularly in rivers), but that could be a topic for another thread.

Having noted the foregoing, I do not have experience pulling all of the different acts typical in ski shows, so I'm not really the best judge of what is best for a show or tournament application. I'm just a lifelong Saturday afternoon ski bum.

MarkBano

 

You might want to try this Mark,

Hook one of your airguides to the motor pick up and compare them on a start.

On a beach or dock start I can be stabilized on speed before the speedometer with the equalizer ever reaches that speed. By the time is gets there, it is over, and it is likely to overshoot causing all kinds of throttle jockeying if I look at it.

I have clogged the motor pickup once in 10 years (it hit a submerged branch) and the boat has been everywhere. It is not a Mercury though. :roll:

jim

 

I might bypass the equalizer tube on one of them in next year and compare the two. Hooking it up to the shaft pitot is a bit more involved, because the hose does not run on the outside of the shaft the way it did on the older Optimaxes. It is all inside so the hookup really needs to be in the engine compartment.

As for your good luck with weeds, I don't know what to say. I mostly used OMC engines over the years but it was before we had shaft mounted pitots! Maybe the weeds are just scared of getting the OMC shaft... :hi:

 

I was just joking with you. I have probably never encountered the weed combination that you have. When I ran rivers with a lot of floating stuff the airguide pick-ups would clog with regularity. They would just scoop it all up. It was not uncommon to have both fail in just a few minutes. The engine pick up is below all of the floating stuff.

Beaching can get the pickups with sand also. I rarely have a failure in either type here at home. The lake is very clean.

Could you just remove the hose from one speedo and put it on the other?

jim

 

That's true, I could just swap up front. With the seats now installed, however, I very nearly cannot get myself back out of there once I crawl under the dash.

My problem this summer, in particular, is that they kept screwing with the dam in Manitowish waters, so the water level would drop and the growing weeds would literally lay over and collected floating weeds like a net both on the surface and below. When I'd make my turn at the end of the lake to bring skiiers back down towards our place, I'd often lose at least one speedo, sometimes it would clear on its own and sometimes not. I would try to avoid those areas but because of other boat traffic and a shallow sandbar that we had to navigate around, I couldn't always avoid it. Even the shaft pitot would sometimes plug up, either partially or all the way. We (the royal "we" - not me, actually) destroyed two stainless Stillettos and one freshly refinished alum prop this year, and destroyed the skeg on my brother'ss engine. It was a tough year. They are destroying the flowage lakes up there because of politics, basically, and a DNR staffed by political hacks who have little or no training to do what they are hired to do and who have virtually no idea what they are doing.

 

I have been stuck up there more than once. I can do it if I take the steering wheel off.

On mine, I can get access by removing the instruments also.

jim

 

I drove in a WI State tournament in the early 90's at Wisconsin Rapids. I took one pass through the course before the tournament started and noticed that I had lost one speedo. This was when the Dyne was still an I/O. I checked for weeds and no weeds. It was sand from when I launched. I had gone straight from the launch to the show course.

I laid down on the observer seat and reached under the dash and removed the line from that speedo and blew it out. About that time one of the safety guys came up in a boat and asked who I was and why I was there. All they saw was me taking a practice pass, then shutting down and laying down in the boat in the middle of the course. They had never seen me or the boat before.

I guess they were happy with my explanation.

jim

 

You used to be able to get a special valve and compressor setup which allowed you to clear blockages at the press of a button. The compressor pressurizes the line and the valve stops it from getting to the speedo. I don't usually have a big problem with weeds, only occasional bad runs if there have been floods but if I did, I'd be rigging something up.