Welcome! Need support, you got it. Or share you ideas and experiences.
In Reply to: Re: homemade outboard posted by KenOhki on March 15, 2003 at 02:32:54:
Its raining dogs and cats out here in so. california. I needed to do some welding before I proceeded to the next step. since I weld outside and its raining I did not get anything done today.
On the homemade boat issue my biggest worry is that it will sink with my wife and I in it, but with the outboard the worst is that the motor will end up on the bottom. (Good idea about the tethering the outboard to the boat, I will definately do that)My biggest worry about losing the outboard to the water is the joint between the pipe and the door hinge. It is not supported by braces, it is under a bit of stress, and I am welding two different types of metal there (galvanized steel and some other type of steel). Soon as I can I am going to weld the inside of the pipe as well to the door hinge if I can get the welder handle enough in the pipe.
The lower end is kind of a difficult issue. Your drawing and idea is excellent and would no doubt work. (that photo shop program you use looks really efficient by the way) I especially liked the way it took advantage of the bearing bolts to hold it in place, something that I was having trouble figureing out using the pvc. It does use an access panel which I need and is more hydrodynamic. I am not sure how to preceed there yet. I wanted this outboard to be made junkyard style, out of parts that are easy to get with minimal customization. I want it as simple and as easy to fix as possible. If I slap somethig together junkyard style and it meets the minimum 5 mph that I am looking for then I am happy, if not then I will have to make some performance modifications. I have been thinking a bit about the pvc parts and want to try something with them first. Even though I could not find threaded ends,(I did buy a non threaded 4" tee with caps and pipe) I dont think that I would need to glue the end caps in place. The T is desinged to have a pipe go in it then the cap on the pipe. I want to cut a length of pipe like 2" long to mate the T and the cap. I will glue the cap to the pipe for both ends of the T. But where the pipe goes into the T, I will use a seal like your rubber innertube idea. Since I do not have a inner tube avail but do have rubber surgical gloves, I will try to make an o-ring or something like that out of them-if that fails I will buy an innertube and try that. I plan to then grease up the pipe and then hammer the cap/pipe into the T and then test it to see if it is watertight. One question though is if it fits really tight and is watertight great, but will I be able to pull it out again? I have considered drilling a hole in the center of the cap, putting a bolt thru it, sealing it-this would allow me to grab onto it to pull the cap off. The PVC T idea no doubt is not very hydrodynamic, but I think it might be easier for me to put together and if it works great, if not I will use the fiberglass (I have never worked with fiberglass by the way). Looking ahead of these problems, one has been bugging me. How to attach the prop to the 5/8" shaft. Since this is a critical part, I want it to fit nice and straight with no wobbeling. I have even considered having a machinist do this for me but would prefer to do it myself if it can be done adequatley. Its hole is less then 5/8", the guy who sent it suggested that I bore it out to 5/8". I am concerned about boring the hole perfectly straight thru, once that is done, I have to drill a hole thru the prop and shaft that is straight thru..not easy to do these things with a hand drill. Another idea was to put a threaded bolt thru the shaft hole in the prop that fits snug, put a nut at each end of the prop, tighten. Then somehow attach the bolt to the shaft so that it is straight and level-thats the problem, if its even a bit off and the prop shaft is spinning at 2000 or more rpm its going to vibrate and wobble big time. Ideas?
Hmm, lets see here.. about the hindge deal,, How about bolting matching steel to the hindge then weld to your pipe. or perhaps figure a way to get a U-Bolt on it there. One other lesser Idea would be to incorperate some Bunge cords. tied in the middle to yourlower unit shaft, and connected at both ends to the transom of the boat. It will add some stabilization, yet still alow for tilt.
I am a little unclear as to what you described for the PVC pipes but I am aware of the general disign you intend.. I would not greese them in order to hammer them together. try something like soapy water first.. if I am not mistaken, both ABC and PVC do not respond well to hamering, So try to be gentel. I would try to compress it together with Like a car jack, if you can find someplace to prop the jack and the pipe together and get compresion. Now, getting it off again. a bolt mounted and sealed in place might allow you to dissasemble it. I would definitly use as large a washer as possible on the inside.
Dont worry about working with the fiberglass, Its almost like doing paper machea. If you require help on that issue Ill get into it in more detail. Fiberglass is wonderouse stuff.
On too mounting the prop.. I would strongly suggest you mount it exactly the way a standart outboard would mount. Reduce the size of the shaft and thread it with a tap and dye set Drill a hole in the shaft before and after the prop.The hole before the prop is to lock the nut with a cotter pin, the hole after is for the shear pin that will grip the prop. Drilling that shaft could be a problem, But it really is the only accepted way to do that.. as far as reducing the diamerter of the prop. let your motor turn it and put a metal file or grinder to it.( make sure you brace the shaft so it dosent warp ) Using the motor to turn the shaft will insure a even reduction, You will probably have to grind 3 too 4 inches down the length of the prop and then Dye it that far down the shaft. I would drill before I dyed. You definitly do not want to use welding in any way shape or form to mount your prop. I would not drill out the prop. If I am not mistaken ,, your prop should have a rubber bushing inside of it. It best not to mess with it. ow yeah, If you have a choice, use a fine thread dye as oposed to a course thread one. I dont think there is really a junkyard methoid to attach the prop that I would trust. Not if I wanted it to last more then a hour or so. If yo do decide to drill your prop, I dont think drilling it straight is really a concern, the prop already has a hole, and that will asct as a pilot hole and pretty much guide the drill bit in straight. Just take your time and drill slow.
Got a little bit of work done tonight. Had to work late on my job so I will not comment so much tonight. I will probably go with your idea about using a file to reduce the shaft diameter. Does this work well, have you done it?
Updated photos below.
Yes, I have done the shaft reduction in a similure manor. I have used both a file, and a hand power grinder, as well as once with some wet sandpaper when I got down to the end when I just needed a little more.. Getting it to the exact diameter might be a touch tricky but not impossible. DOnt overgrind, remember you need to leave materiel for the threads to be cut into. I would use some scrap wood with a hole in it the size it needs to be and use that for a guide.
Looking at your latest pictures, My only real concern is the shell moving and binding your shaft. Getting all that mounted together solid might be a bit tricky. Im not sure I have any valid sugestions for that. perhaps you can utilize a couple of hose clamps passed through slots on the horizontal pipe obove the waterline to secure it, A bolt or 2 like in my pictured wooden design would also work, But I think you really, ( and I mean really really ) need a secure mount on the botom. I supose the stuffing box is a anchor point, However something is naggin at me saying ya need a bit more. Maybe not,, Like I said,, I usualy design things much stronger then they really need to be.. Probably becuse I am rather hard equipment sometimes hehehe.
I have 3 5/8" rods (shafts) to work with so I will have some room for error with trying to reduce the diameter. Lets say the prop hole is 1/2", do I grind the shaft down to 1/2" then thread it or do I grind it down to a bit above 1/2" then thread. Also, the cotter pins that you mentioned, do these cotter pins go thru the shaft so I will have to drill through it? Lastly, what is that thing that is inside the prop, I can take it out, it looks like it might spin inside of the prop, cant think of what purpose it serves.
Not sure how I will attach the housing. I am hoping bolt middle vertical pipe that goes down to the T directly to the metal inside pipe. Then thread the T to that pipe, once threaded in place it might be stiff enough to hold the lowerend in place without having to anchor it. I will have to assemble the outbourd and look at this to see if it will fit together nicely. If the ABS pipe runs along the upper galvanized pipe, its will would lie flush if it were not for the reducer halfway down. I am thinking that I might use washers at the connection points to make up the the small gap that the reducer creates. I dont know if this arrangement is going to fit or work, just kind of doing it by the seat of pants. I have not been able to get any work done on the project lately and it will probably be a day or two before I can work on it again. I really look forward to the "garbage can" water test to see what happens.
That thing inside, If I am not mistaken, is round chunk of kinda hard rubber. ( at least on the props I have seen ) as far as I understand, it helps absorb shock and allows for it to wobble minutely without comming all apart or vibrating. I believe it is called a bushing. Yes, the shear pin or post behind the prop and the coter poin hole in front both need to be drilled through the shaft. In the back you need a strong Pin, this is what will have to stand up to you torking down the shaft nut
About your grinding to size. I would determin the size bolt that fits through the hole of the prop, then drill your guide to that size. I would make a note of how snugly the bolt fits in the hole, and keep that in mind when checking the shaft. Personaly, I would want the shaft fitting in the guide hole just a smigeon snugger then the bolt does, seams to work for me when I use the dye.
Did not get alot done on actual construction tonight, I went to home depot with the lower end trying to figure out a way to connect the ABS to the steel tube. I am going to try to use a u-bolt at the upper ABS pipe to hold it in place, and then use your idea about taking advantage of the exising bearing bolts to hold the lower end in place. To do that I bought some longer 1/4" bolts that go thru the bearings. I forgot to buy the smaller motor mount bolts while I was there. Maybe I will get by with the bolts that I have although they bind big time. Hopefully being bolted in those two places will be enough to hold the abs in place adequatly. I will have to wait on the prop until I get the rest of this finished, the more I think about attaching that prop correctly the more I worry about it. Updated photos below
I am sure if you use the bearing bolts to secure the ABS in the prescribed manor that it will hold it. I didnt make a special design note but I hope you are intending using many nuts on each beering bolt, 1 or 2 to tighten the bearing to the plate, then other nuts further up the shaft to hold the abs Id probably use 2 to lock them together at the right hight. Might be a bit tricky working in that tight area..
Acared of the prop huh? I wouldnt worry too much about it.Although ita an important thing, It is not a difficult one.. If the shaft is actualy thick enough to bore and tape out to the prop hole size that might be another way to go, However the exsisting method I recomendid I still see as best.
I have to apoligize for the very slow progress of this project. I have had my taxes to do plus the war on CNN plus my lack of know how which have resulted in delays hehe. I have learned a huge amount doing this project though, a little bit about everything,much thanks to your input, if I did it again it would not take nearly as long. Regarding the bearing bolts, I have a bag of nuts and washers to use up so it should be no trouble to use many to hold it in place. I bought some neoprene washers to use to waterproof it, not sure that they will work-I can always caulk it or something. The problem is that the existing 1/4" bolts are too short and the only longer ones I can find are like 5 inches long (I want them threaded from top to bottem-Ihave to keep the 1/2" motor mount bolts because I cant find anything slightly smaller threaded all the way up). I will cut them down with the grinder/saw but I worry that I will be unable to thread a nut on it afterwards. All I was able to do tonight was drill a couple of holes thru the abs to the bearing plates then it occured to me that I will be placing a flat nut head and washer on a round curve, wont be pretty looking. I will be trying to grind the shaft down with a file first but what did you mean about boring out the shaft and and the tape out in your last post? No updated photos, hopefully will get something done tomarrow.
One must work at ones own pace, so dont feel preusured to complete on my or anyone elses account ;p
Personaly, I would use a hacksaw to cut the bolts down to size, then a fine tooth file to smooth it all up pretty like. You can also taper the end of the bolt a little wile cleaning it up with the file, wont hurt anything, and is easy with a large margin for error.
About the flat nut on the round ABS thing. It shouldnt look too bad, I think you will have to resort to RTV silicone or something similure for a seal. If you are really concerned with a flush meeting of nut to abs there you can always cut yourself some custom spacers flat on top for the nut, and slightly curved on bottom for the ABS out of wood or some other available materiel.
On to the taping of the shaft.. Small typo here, that should be TAP not tape hehehe.. I am not sure of the diamerters you are dealing with. But what I was trying to say was If the shaft is suficiently larger then the hole on your prop. You might be able to drill the shaft and tap it out to recieve your bolt through the prop into the shaft. One drawback to using this method, You will not be able to lock the bolt in place, you will be relying solely on 1 bolt without a cotter pin. a locking washer or 2 might help.. it is possible to drill through the shaft & bolt and put a cotter pin in behind the prop but still through the shaft and bolt if this method is employed, But this is not a recomended way, Just an alternate way. Something that would work if it had too. ( if the shaft is big enough. In my experience, as long as you have 1/16th of a inch sidewall after taping, you will be alright, if it is less, the sidewall might giveway under load ). Personly I think reducing the shaft diamerter and using s dye on it is the best method, it allows for you to be able to lock the prop on with a pin. Hmmmm... It occures to me here that you can always tap the hole smaller then the prop hole if need be, and use spacers on the bolt build it up to the prop hole thickness. but as stated, this is not the best way, Just A way. If I have failed to decribe this good enough I can knock you a picture together
I was just sitting here thinking I feel just like my old shop teacher here, He used to present several ways to do something but let us decide which was to be used.
Sidenote here. buddy of mine, also adept in making adatchments. ( no typo there) an Adatchment is a term we coined a few years ago wile creating animitronics for a haunted house. An Adatchment is a part, usualy an handmade custom adapter that connects 2 or more things that dont go together, In order to make them do what You want them too, reguardless of what the parts were originaly designed for.
Anyway, after discusing this prodject with him a few different times as we have progressed here, He is now looking at making a Jet water drive for his rubber raft. That should be a challenge. weight is a real issue in a rubber raft. Im thinking weed eater here as a powerplant, but I am still undecided. Either that or a chain saw. but thats another story. If he persues it this summer Ill start a new thread for its discusion.
Finally got some time to spend on the project but accomplished little other than learning some stuff. After I put the bearing bolts in place with the longer bolts(got to warn you, not a pretty site hehe), the lower T and pipe houseing would not align properly (probably because I did not drill the holes properly alinged-its harder than it looks). Finally I took out my rotozip cutting cool and cut out some of the upper portion of the pipe and an access hole in the lower portion of the T to allow the lower shaft assembly more room to move. The assembly alinged barely ok after that, not nearly as clean as I hoped it would be. I assembled the outboard and started it up and it ran ok without too much belt interference or vibration. But I am overall disapointed with it, its just not as clean and simple as I wanted, I am having to "Macyver" everything now and it is making the project too custom and complicated. My goal was a simple assemly that could be easily replicated again. Starting to lean towards your plywood/figergalss idea but not quite ready to abandon this idea yet. Anyways.. Will have to patch that bottom access hole and upper cut, I think fiberglass might work for that, where do you get that stuff by the way? I have never worked with fiberglass but know of it and the way I envision it is that you lay some type of fabric then paint the fiberglass glue on top? Lol on the adatchments, that is a perfect term for what is gong on here.
I hope that your friend goes ahead with his project and cant wait to see the photos and progress. Update photos below.
hehe yeah your end product is starting to look a little Uhh,, Rough. Pretty standart for a prototype. hehehe
fibergalss can be purchased at any mareine supply store, Walmart, and your better hardware stores. at least around here. Auto parts stores like napa also carry it.Make sure you get resin,hardener and mesh cloth. DO NOT buy tigerhair fiberglass for this.
Here is a quick fiberglssing lesson, at least,, this is how I do it, and My glass jobs have never failed.
A- clean area to be glassed.
B-rough up the area to be glassed with a med to course sandpaper.
C- Lay a clean empty 2 litre plastic bottle on its side and cut a large Oval hole in to serve as a disposable mixing containter.
D- Wear rubber gloves
E Cut your mesh at least 2 inches wider and longer then you need to cover the area.
F-mix resin and hardener in the cut open bottle, drop the cloth in and stire and kneed it til it is fully saturated. ( be fast, speed counts )
G- wrap soaked mesh around the pipe and smooth out as best you can. Speed is more important than neetness. You can always sand for neatness. Try to work neat, but speed is really the key.
H - Let dry a few hours then sand.
Some notes here. Once the mesh is laid, do not peel it back up. You can slide it a little but its best to place it where you need it first shot. It would probably be a good idea to put the piece you cut away back in place before fiberglassing. how much hardener you use determines how fast it will set. too much it will set super fast, Too little and it wont set at all. it is better too use a little more then not enough if unsure when mixing. for your aplication 1 layer should be enough, 2 would be better, 3 should be stronger then the pipe itself. I think after you use fiberglass once, it will become part of your standart bag of construction tricks.
One other note about working with fiberglass, it will produce a certain amount of heat due to the cemical reaction to the hardener. this is normal, and sometimes feels very warm, but not enough to burn you.
This post is made possible by the generous support of people like you and our sponsors: