We Went Back In Time To Make Our Boat Go Faster...

[Music] i wanted to do an update on our catamaran boat project it's fun to pretend that we probably should [Music] cause [Music] a couple of months ago we took this boat that we built out to lake willoughby in vermont and we spent the day with a bunch of friends and we ran it through its paces and had a lot of fun and if you're interested take a look at the video today what i wanted to do is explain how we've made some adaptations and changes based on the long-term plan for this boat and when we brought the boat out to the lake we found that it was very easily controllable it was more stable than the conventional boat that we used to do the photography from and we're easily able to control it it was silent we got a lot of thumbs up from other boaters and we were able to achieve about five and a half miles per hour or about what eight kilometers per hour with three big guys on board and had a range of about 18 miles with a single tesla s battery module 24 volt battery module used to about 75 percent of its capacity so we used up about three quarters of its power and a few days later we tested it with rather than the conventional trolling motor propellers that came with the electric motors that we used we tried it with these rc fiber reinforced rc propellers that have a little coarser pitch and a better airfoil and we're able to bring it up about another mile per hour another two kilometers per hour with similar current drains so we probably had a proportionately larger range with this other propeller not that much of a difference and so we didn't film that but what it led us to decide is whether or not to continue with the electric drive at this point because the ultimate purpose of this boat is as a test bed for a variety of different propulsion systems electric gas wind and the plan is to add to this system a hydrofoil this hydrofoil here is an naca 0009 extruded aluminum hydrofoil design it's actually almost identical in its profile to the hulls that we built out of fiberglass and wood last year and we obtained this from duck works you can get this in long segments and then they simply trim it you can then use this as a hydrofoil saves a lot of work this was intended to be mounted here about midships and to be supported by two legs from this cross beam that was put in for that purpose and the location of the cross beam is slightly in front of the center of gravity of the boat if we've got somebody up here controlling it and a couple of people sitting at the midpoint of the deck the reason for that is that as the hydrofoil lifts the front of the hulls out of the water the rear part of the hull the stern will actually still be skimming in the water this is similar to the old russian hydrofoil designs or the disco volante if you remember the old bond series the reason for doing that is because as i've said before engineering is the art of compromise and in a lot of hydrofoils you'll see that they try to elevate the entire hull out of the water that tends to be dynamically very unstable by leaving the rear end in the water it tends to be more stable it will require a little bit less dynamic control to keep the boat from riding up too high or too low it also allows the control surfaces such as the rudder or potentially a propeller or some drive system to remain at a constant depth that makes it a lot easier in terms of engineering rather than some shaft that has to be articulated or sent you know another meter or so below the boat it becomes rather complicated because of the fact that we need to elevate the front of the boat and we need to lift about 250 kilograms out of the water there are equations that you can take a look at we'll put a link in the description below to some formula that allow you to determine the amount of lift that a hydrofoil will make but a well-designed hydrofoil and this is a pretty typical design in terms of its shape located at least half of its cord below the surface of the water and the cord is the width of the of the of the foil so if it's located at least half that distance below the water level you can calculate how much lift a given area of foil will produce for a given velocity through the water and what we calculated is that in an ideal setting we needed about 12 miles per hour or about 18 kilometers per hour in order to be able to lift the front of the boat out of the water so it was questionable whether or not electric would allow us to do that as we had it configured now you might think it's not questionable it's obvious it wouldn't you said you only got to maybe six and a half miles an hour half the speed it's not necessarily true that you wouldn't be successful because the hydrofoil will produce lift at all velocities and has such a minuscule drag inherent in the hydrofoil itself that as you begin to move forward and you begin to elevate the hulls a little bit you reduce the drag as you reduce the drag you increase the speed that any kind of drive system can reach therefore you increase the lift which decreases the drag which increases the speed and so as the velocity is going up and the lift is increasing the drag is decreasing and eventually these two curves might meet based on our calculations and my estimates it would be a very close thing we might be able to do it but i thought it might make more sense to give ourselves some additional power to give us a greater likelihood of success when we put the foil on so what i did is i removed the module for the tesla battery and the two electric motors that are on the back of each of the two hulls and replaced it with what's called a long tail or a tie as in thailand long tail gasoline powered motor now these are interesting motors and that's what i want to talk to you about today they are actually first popularized maybe even invented in thailand decades ago and they're an extremely simple type of gas propulsion system they're less expensive per horsepower than a typical outboard as you'll see there's a good reason for that the motor here is a six and a half horsepower harbor freight motor you can pick one up locally at for about 119 if they're not on sale and because it's a four-stroke motor it's efficient it is air-cooled therefore we're not depending on water flow from questionable water sources that have to get into a typical outboard a lot of people are pretty comfortable with maintaining and taking care of motors like this and you can also use them at temperatures that would be possibly close to freezing and could endanger the water cooling system in a typical outboard wise the overall cost of this is still less because the kit that we bought from sps swap motors which i think based on some videos that i've looked at and some people that i've talked to it's probably one of the better quality simple straightforward uh long tail motors that kit costs about four hundred dollars so you end up with about a five hundred and fifty dollar six and a half horsepower motor so it's still less expensive than a new outboard and as the power levels go up you can get up to 22 horsepower here the prices don't go up very quickly so it becomes progressively even more cost effective part of the reason we want to do this is i thought it would be fun to just play with one of these motors but there are other reasons why and i'll show you when we go around to the back before i leave this part of it though let me show you how we mounted this the typical application is to put this on a transom but because of the fact that i wanted this under the deck and out of the way but also at a balance point where we could easily start it and we can access the controls i wanted it to the front where the person sitting there can do this on the side of their hip in order to do that i can't a levered off the off of this bar that's holding going to hold the hydrofoil with a couple of light weighted uh aluminum fabrications that i machined in order to hold the motor at this location here but still bolt it back here i lightweighted them trying to just remove as much weight as possible because they're overly strong and they also look kind of nice they look sort of aircraft like so it's kind of a nice appearance in addition the uh control arm for this motor typically just sticks out in front if you're sitting in the back of a john boat or in a flat back canoe and you've got this mounted on a transom this bar that allows you to control the motor would normally stick straight out i cut it rotated it and welded it so that it would go up in this direction to make it easier for the user and i'll i'll show you demonstrate how this works in just a little bit what i want to do though is i want to go around to the back of the motor and just show you how these things are designed and how it's set up so you get an idea of how simple they really are all right you can see it's pretty simple if you look way up here to the back of the motor you'll see a fabrication that has a flange that mounts directly to the flange plate on the back of the motor and then there is a compression lock that supports a heavy wall galvanized steel pipe that extends all the way back here and then has bushings located all the way up the length that are greased and they support an internal solid steel rod we elected for the slightly more expensive stainless steel rod so that it would have more corrosion resistance in case we use this in sea water then you have a prop mounted on the back of this thing and that's it it's that simple it's a direct drive system it is about the same weight as a typical outboard of the same horsepower it's obviously more bulky and it does not have reverse its direct drive you can get variations on this that include articulations and belt drives that look a lot more like a diy outboard motor but in its simplest manifestation a tie long tail that's all it is a pipe with a supported rod rotating within it you can see it's actually made in thailand and one of the big advantages of this motor besides the fact that it is less expensive is that they are also called mud motors or swamp motors because they are very tolerant of very poor water conditions because of the fact that you have a very shallow angle of approach for this propeller what happens is if you run into logs or gravel or rocks the prop will just bounce over them it'll just run right over the right over the obstructions you may damage the prop but you can pick new props up for about twelve dollars you can install them with a little puller in the field and you're almost certainly not going to damage the shaft or the motor in any kind of uh hit that you have with any kind of obstruction this particular model here as you'll notice and most of them are the same way tends to be bow or prop heavy and the reason for that is because of the fact that when you have a propeller that's located a little below water level the downward rotating blade is pushing down into the body of water but the upward rotating blade tends to be not that much below the surface of the water and pushes the water out up off the surface so there is a greater force downward with the propeller than there is upward and so the entire end of the propeller or the entire end of the shaft tends to lift the propeller out of the water as you increase speed and increase uh force of the propeller against the water this actually tends to lift up and so if this was not prop heavy this would tend to bounce out of the water when you got up to speed and so they've designed this thing to be heavy enough and you can adjust that so that when you get up to speed on your particular application they can be so well balanced you can actually control them with two fingers you don't have to be cranking the thing in the water trying to keep it into the water rather than having it bounce out now on a typical application with say a flat backed canoe or on a john boat the sps people will send you sell you or provide with the kit this very heavy metal bracket it's really robust and it has clamps that allow you to clamp it on the back of a transom and then a welded pipe here that allows a yoke which is mounted on this post here which inserts into the pipe and little retaining bolt keeps it from popping out so that this allows you to turn the motor in order to be able to steer now in normal applications that long pipe moving in the back of the boat can sometimes be a little bit of an inconvenience but in our particular application it would be useless because when you have a typical boat and you have a motor on the back of the boat when you turn the tiller or use steering to change the angle of thrust you actually push the bow or the stern of the boat one way or the other which turns the boat that's how you rotate the boat about its pivot point or its point of buoyancy in our particular application because we would have to mount a single motor either here or in front we're much closer to the center buoyancy of the boat so if we turn the motor at this point we're close enough to the center that rather than causing the boat to turn it will actually try to force the boat sideways a poor method of control so that's why what we elected to do is to get rid of that part of the kit and mount this on a pivot that only allows this to go up and to go down rather than making a feeble attempt to try to steer using the motor as a consequence what we needed to do is we needed to incorporate some method of steering that not only would work with this but potentially with other types of propulsion certainly like sail or a kite sail we would need to have something like rudders okay so let me talk to you now about the rudder system for this uh this design if you remember from the first video we did not the trial we had out on the lake but the first video we constructed the boat i explained that the philosophy behind this design was to produce a modular system that would allow us to transport a relatively large boat on a small trailer but to easily be able to construct and assemble and disassemble it so that you can transport it and set it up relatively quickly so in order to control these two remote rudders from a long way away you really have to either use a hydraulic system or a pulley system you might use a long articulating arm like you have in a sailboat but then you've again got a lot of long pieces of hardware and a hydraulic system tends to be kind of bulky and so what we elected to do is to go with these 12-volt linear actuators that connect to the rudders and allow us to plug this in and run wires rather than hydraulic lines or pulleys that would have to be reconfigured each time you put the boat in the water the installation is very simple just a couple of nyloc lock nuts that when you snug them down they're not going to slip off or vibrate off you can do that by hand and then the entire actuator can be lifted off and unclipped and unplugged and that allows you to put that in the back of your truck and then you have a free rudder here the rudder itself can be removed from the back of the boat because i have a small little retaining clip located on the top here that prevents a rod from sliding out when i pull the clip out i can then take the rod push it up from the bottom and pull it all the way up out here like this i just threaded the end of a stainless steel rod and put a little lock nut on the top to keep it from falling through and then the entire rudder simply pulls out i've got a couple of grudges back here that allow these fittings on the back of the rudder to simply slip in and then are retained by a couple of screws in the back of the rudder assembly and then this plastic that i've mounted here like this fills in the gap and provides a little bit more hydrodynamic flow rather than having a large gap between the two structures and a flat surface here may not be that necessary but i think it wouldn't hurt and then there's a little groove mounted or milled in here to allow the rod to pass all the way through the entire thing can easily be put right back on like this you take the rod you place it into the hole in the top drop it through wiggle this a little bit get it in there and then you simply place the retaining clip in there to prevent it from lifting up and that's it very simple the arm here is a compression lock essentially what i did is took a bar of aluminum uh drilled a hole in the middle of this uh fabricated a threaded hole over here and then put a small slit in the back that allows us to compress onto here so that we can make fine adjustments in the relative angle of these two components and then simply lock them down with a bolt and this compression is a very very solid way of establishing a strong joint at this point here and then once you've decided that you want to go ahead and use the rudder you just take the articulating actuator drop it over the two holes like that snuck it down and you're ready to go it's that easy the rudder itself was designed using what's called stress panel construction and i went over that a little bit in the first assembly but what i'm going to do is in the next video i'm actually in a couple days we're going to put out another video and i'm going to show you exactly how we built this it's a very very time efficient method of producing very strong very lightweight structures that don't require jigging and fixturing or even milling machines or high-tech equipment and you can produce very quickly very rapidly very good structures that you otherwise would have a lot of difficulty building in any other way so that's pretty much it for the review in terms of the structure let me show you how this actually operates all right [Music] it'll stop on its own [Music] and then reverse it a lot of power plenty of power and the the electrically switch over so they won't run any farther than their 12 inch or 30 centimeter design operating length and then you just reverse the switch so now what i'm going to do is i'm going to go up in front and let me just show you how i actually wire these things in so this is the control rod and you can see located on here is the kill switch that comes with the kit you simply pull on this lead right here that would be hooked onto you and it'll kill the motor for safety in addition up here is the throttle control and the handle that would allow you to be able to adjust the speed of the motor and then what i fabricated was a simple reversing switch that allows you with your thumb while you're controlling here to be able to move the motors forward and backward now the way that this switch operates is it sends power from this battery which i've just placed a waterproof velcro attachment to that allows me to mount this on the front here and easily remove it when we're ready to take the boat apart runs the power into the switch here and as you can see in the diagram this is how a double pole double throw switch can be used to reverse the direction of a dc motor the power is sent in to the middle of the six leads in this dp dt switch when you flip the button in one direction you send the power positive goes directly to positive and negative goes directly to negative but if what happens is you push the button in the other direction and you actuate these two connectors here these are now unconnected and you simply send the power from the positive to this side and from the negative to this side so anytime you want to have a reversing switch just using one of these dpdt dpdt switches you can easily use them to reverse the control of the direction of any kind of a dc motor then after wiring them up because this is obviously going to be potentially a wet environment i then potted this in some two-part silicone that covers all the wires and the connections and the switch itself and the switch is a wash down switch the which switch can get wet but nevertheless i didn't want the connections to corrode and then this is simply clamped onto the post here by cutting a small trough in the back of this block of aluminum and putting a retaining plate that compresses against the um this other side of the pole so this allows you if you loosen this to slide this up and down as well as to rotate this to get this right in the position of your thumb and when you're sitting there this works like a top gear connection it's very easy for you to steer with your thumb and control the throttle with your uh four fingers and then when you're running the motor or starting the motor you can push this down like this and without this paper here you'd have plenty of slack in the wires you're able to move this thing up in order to reduce the resistance so that when you start the motor it's easy to get it started and then when you dip it down into the water if you adjust the pivot points right it should just float there and you're easily able to control the direction and the speed of the bow so that's pretty much it so i'll see you in a few days and i'll show you how the rudders are constructed if you have any kind of a comment please i read them all and i try to address as many questions as you have hopefully i can clarify anything that i didn't cover in enough detail in this part of the video we'll see in a few days and you have a wonderful afternoon take care [Music] you

Channel: Tech Ingredients

Views: 101,727

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Id: jYoS8JnCZpw

Length: 24min 2sec (1442 seconds)

Published: Fri Oct 30 2020