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#51
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No Spam wrote: "Tinkerntom" wrote in message oups.com... Hey Wilf, You never said that I can find, what sort of roof rack do you have? Is it a Commercial unit? If so, most of them have some sort of extender system already made. No point in reinventing the wheel. The problem with electrical conduit is two fold. First it is steel and would begin to get nasty fast when exposed to salt water. Secondly, it is designed to bend, which is great in some projects, but you would not want it to decide to bend when you have the kayak on it and lifting other end. It would result in a loud crash, and possibly a broken boat or twisted back as you try to keep the loud crash from happening. Any of these scenarios being bad. I think you will also find that the commercial extender systems do not extend as far as you are thinking like up to 28". So, though they use extruded, hardened Aluminum, which is amazingly strong, they only go out like maybe 15". Go out any further, and they don't bend, they break right of, and you end up with a similar scenario as above. So it may be time to go back to the drawing board! You might think in terms of Titanium, and then you begin talking real money, though with the aircraft industry up there, you may have a cheaper source! What you need is a material that can take the extended end loading, you might think of a fiber glass or Kevlar pole, which could be extended out beyond the side of vehicle, and supported in the middle folcrum on the roof gutter independent from the existing rack. This pole could extend across the top of the vehicle and be attached for loading to the other end of the rack. Think in terms of a teeter-totter, with one end held down, and the other end sticking out beyond the side of your car. The right material can carry a significant load. The right material could even be just a clear of knots, straight grained piece of Douglas Fir. A hand selected 2x4, from the local lumber yard. Trees are subject to end loading by the wind, and are incredibly strong. When you are done loading your boat, the system will not fold up all nice on top like a commercial unit would, but you could pull it and place inside vehicle, or lash along side the kayak on top. Now your car begins to look like a kayakers car should look. Check out the pictures on Wilko's website, and you will get a better idea of where this is headed. :-) My only other suggestion also, is that when you lift the front end up on the extension, that you tie a loop of rope around it to act as a safety to keep it from slipping off the extension as you lift the back end. this would be especially important if it is windy, or you are parked on a slope, which could result in the front end sliding off or deciding to take a lesson in "flying like a kite!" and you are holding on to the little end of the kite. I am sort of like a bull, when it comes to loading stuff as you know (:-), and I just lift my 70 lb boat onto the top of my Caravan. One time the wind caught the boat as I had it overhead and did a windvane number on my back. I am re-thinking my loading procedure even as I write this all to you. It is amazing how you get smarter each time you try to break something. TnT How about seeing if you can get a section of Schedule 40 pipe about 3ft long by 1 1/2 to 2 inches and attach it to the rack (no rust). Then get a good length of hardwood dowel that fits inside. It could be very loose fitting if you have 3 ft of it inside the pipe. I'm thinking 1 1/2 inch OD pipe should work great with a 1 inch or 1 1/4 inch dowel - like you buy to hang the cloths up in your closet. Toss the dowel inside the car when done (if the paddles fit, so will it). A dowel this size with 3 ft of support should hold for most boats. I would think it would hold 100 lbs distributed across the 2 ft or so you have sticking out. -- Stress test away from the car - I don't want to get blamed for a paint job after it breaks ; The beauty of using wood is you should hear it start to fail before it lets go. Unlike the conduit which may just fold-up without a sound. Ken Ken, the only thing I would question, is that where the dowel comes out of the pipe, would represent a sheer line. All the load on the extended dowel would be concentrated at the sheer line as a breaking force. You would not be able to take advantage really of the flex of the dowel inside the tube, to dissipate the energy as a flexing force, and it would tend to break at that sheer line. You are right on though about hearing the dowel break. Another function of the safety line that I recommended, is that if the extension collapses, the boat would not fall clear to the ground. Considering the car paint though, it might be equally important to use some cushions in strategic spots in case the boat fell. You could just hang a long noodle on the side of the car to take the bang. or like Cyli indicated, you just don't worry about the paint! TnT |
#52
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"Tinkerntom" wrote in message oups.com... Snip Ken, the only thing I would question, is that where the dowel comes out of the pipe, would represent a sheer line. All the load on the extended dowel would be concentrated at the sheer line as a breaking force. You would not be able to take advantage really of the flex of the dowel inside the tube, to dissipate the energy as a flexing force, and it would tend to break at that sheer line. You are right on though about hearing the dowel break. Another function of the safety line that I recommended, is that if the extension collapses, the boat would not fall clear to the ground. Considering the car paint though, it might be equally important to use some cushions in strategic spots in case the boat fell. You could just hang a long noodle on the side of the car to take the bang. or like Cyli indicated, you just don't worry about the paint! TnT You are correct about the shear at the point of entry but I think a hardwood dowel of this size will take this force without complaint. My uncle used to hang an old wood extension ladder on dowel pegs and it took 2 people to lift that thing down. The flex in the exposed dowel would take the force of the jolt of rough handling of the boat though. I did some google searching but cannot find the shear strength of a dowel but I would guess that a 1 inch hardwood dowel would take at least 500 pounds of pure shear force before it would break. I have a 1 1/2 inch dowel here and I just stood on the end of it with the other end wedged under my work bench -- yep lifted the bench right up - the dowel flexed a little but easily handled me 275 lbs out about a foot from the support. Ken |
#53
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On Tue, 15 Mar 2005 14:50:11 -0800, Peter
wrote: Cyli wrote: On 14 Mar 2005 19:02:10 -0800, "BCITORGB" wrote: (snipped) Hmmmm... now you've got me worried. Just to check, do you have expertise re van doors? I don't, hence my worry. I wouldn't have thought that approx 50 pounds at the mid-point of the door frame would be too much for the door-to-frame connection to withstand. However, I haven't a clue. Does anyone else out there have any opinions? Cheers, Wilf Only a few damaged car doors. Not by boats, but by kids. The doors did stay on as long as they were kept locked closed and tied to the frames if necessary, but that mean exiting through the car window, which could be undignified, especially in a skirt or dress. To what kind of forces were these doors subjected? Damfino. It was kids. They stutter and stammer and wobble when questioned. They evade and say that they don't know or XXX did it. In one case, the car was that way when the kid bought it. All 3 on inexpensive American mid sized cars built in the 60s to 80s. Cyli r.bc: vixen. Minnow goddess. Speaker to squirrels. Often taunted by trout. Almost entirely harmless. http://www.visi.com/~cyli email: lid (strip the .invalid to email) |
#54
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No Spam wrote: "Tinkerntom" wrote in message oups.com... Snip Ken, the only thing I would question, is that where the dowel comes out of the pipe, would represent a sheer line. All the load on the extended dowel would be concentrated at the sheer line as a breaking force. You would not be able to take advantage really of the flex of the dowel inside the tube, to dissipate the energy as a flexing force, and it would tend to break at that sheer line. You are right on though about hearing the dowel break. Another function of the safety line that I recommended, is that if the extension collapses, the boat would not fall clear to the ground. Considering the car paint though, it might be equally important to use some cushions in strategic spots in case the boat fell. You could just hang a long noodle on the side of the car to take the bang. or like Cyli indicated, you just don't worry about the paint! TnT You are correct about the shear at the point of entry but I think a hardwood dowel of this size will take this force without complaint. My uncle used to hang an old wood extension ladder on dowel pegs and it took 2 people to lift that thing down. The flex in the exposed dowel would take the force of the jolt of rough handling of the boat though. I did some google searching but cannot find the shear strength of a dowel but I would guess that a 1 inch hardwood dowel would take at least 500 pounds of pure shear force before it would break. I have a 1 1/2 inch dowel here and I just stood on the end of it with the other end wedged under my work bench -- yep lifted the bench right up - the dowel flexed a little but easily handled me 275 lbs out about a foot from the support. Ken Ken, Wilf, is talking about extending the dowel out 28", see what loading the dowel breaks under now. This will prevent Wilf from falling off his workbench, and you seemed more inclined to do this sort of stuff! I mean testing, not falling off your bench! TnT |
#55
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Hey, you guys have been great! I still don't have my solution, but I
think we're getting there. In review, my own particulars a a '94 Ford Aerostar where dents and scratches are not an issue (Hell! It's an Aerostar! Was there ever a cheaper van made?!), no commercial roof rack, just the thing that all Aerostars come with, and a short (5'7"), stocky guy who can carry and horizontal lift the 90 pound kayak to a height of about 4.5' (I've not tried clean-and-jerk... maybe after a few beer). After just two trips, I've just about perfected (and really like) the "front end on the front door" maneuver. BUT, Cyli's got me worried and thinking alternatives. I think Tink has a point re the conduit; after all, it was made to be bent. I went to the hardware store this morning and tried a bit of pressure on the pipe and I was able to put a bit of a bend on it without much effort. I then thought of going one dimension larger for each of the pipes (greater diameter = more difficult to bend, right?). I would have purchased right away had it not been for the price. I need to find me an electrical shop that has "ends" (about 4-6 feet worth of ends) kicking about. As an alternative (and it was something one of you said, I'm sure), I could go very crude and very elemental (if the material strength is up to the task). Tell me what you think... Two approx 7' pieces of 1X4. Place one lengthwise, on the left-hand side of the van, under both roof rack crossbeams. Then, place the other 1X4 under, and at 90 degrees to the first 1X4, with about 3' jutting out over the right-hand side of the van for me to place the kayak on (this piece would be secured, with rope, to the crossbeam to ensure it doesn't slip as the weight of the boat is placed on it). Why 1X4? Because nothing thicker than 1" will fit under the crossbeams and still allow another timber to be placed under it. Question to all you bright guys: will the 1X4 be strong enough to hold the kayak? Cheers, Wilf |
#56
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Tink says:
=========== Ken, Wilf, is talking about extending the dowel out 28", see what loading the dowel breaks under now. This will prevent Wilf from falling off his workbench, and you seemed more inclined to do this sort of stuff! I mean testing, not falling off your bench! TnT ============== I'm with you on this Tink -- as far as a 275 pound guy is concerned. The question is, as you point out, what happens when the dowel is extended out 28" and approx 50 pounds is placed essentially at the 14" mark (although, what with twisting and turning, the full 50 pounds could, momentarily anyway, be way out there at the 28" mark)? Tink, you mentioned that you're an electrician: do you think 50 pounds could bend the larger diameter conduit? Cheers, Wilf |
#57
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BCITORGB wrote: Tink says: =========== Ken, Wilf, is talking about extending the dowel out 28", see what loading the dowel breaks under now. This will prevent Wilf from falling off his workbench, and you seemed more inclined to do this sort of stuff! I mean testing, not falling off your bench! TnT ============== I'm with you on this Tink -- as far as a 275 pound guy is concerned. The question is, as you point out, what happens when the dowel is extended out 28" and approx 50 pounds is placed essentially at the 14" mark (although, what with twisting and turning, the full 50 pounds could, momentarily anyway, be way out there at the 28" mark)? Tink, you mentioned that you're an electrician: do you think 50 pounds could bend the larger diameter conduit? Cheers, Wilf Wilf, you say you are with me on this, do mean the testing, or falling off the workbench? I am not sure what you mean by large diameter. We bend conduit all the time with bending tools up to 1". Beyond that we have hydralic benders. This is mainly to provide a standard radius that the wire can be pulled through inside. Otherwise if you were to take the conduit, and bend it over a sharp edge, as soon as the radius of the tube is broken, the tube will easily collapse. There is a certain structural strength to the tube, but once it is compromised, the tube material is pretty soft and malleable. One person that you might check with, is Michael Daly. Recently I saw him post, that he is a structural engineer. He could probably give some good suggestions on real data base. I mostly figure stuff off the seat of my pants, hence the Tinker. My name is a double or triple entendo (sp)! Given enough time, as a practical engineer, I can usually cobble something together! Though it is the sort of stuff you might see on the Red/Green Show. I guess one thing I might ask you though, is how did you come up with the 28" number? Also is your rack a commercial unit, or is it standard Ford issue on Aerostar? As you load the kayak, can you come in at a larger angle to get the bow more up on the vehicle to start. That way the extension would not need to be so long. You would then be standing further out from the vehicle as you lift the stern, lift it higher so that the front does not get pivoted off the front rack, and swing the stern up on the rear rack. Also did you understand about the safety line, which should help keep the bow in place. TnT |
#58
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Tinkerntom wrote: BCITORGB wrote: Tink says: =========== Ken, Wilf, is talking about extending the dowel out 28", see what loading the dowel breaks under now. This will prevent Wilf from falling off his workbench, and you seemed more inclined to do this sort of stuff! I mean testing, not falling off your bench! TnT ============== I'm with you on this Tink -- as far as a 275 pound guy is concerned. The question is, as you point out, what happens when the dowel is extended out 28" and approx 50 pounds is placed essentially at the 14" mark (although, what with twisting and turning, the full 50 pounds could, momentarily anyway, be way out there at the 28" mark)? Tink, you mentioned that you're an electrician: do you think 50 pounds could bend the larger diameter conduit? Cheers, Wilf Wilf, you say you are with me on this, do mean the testing, or falling off the workbench? I am not sure what you mean by large diameter. We bend conduit all the time with bending tools up to 1". Beyond that we have hydralic benders. This is mainly to provide a standard radius that the wire can be pulled through inside. Otherwise if you were to take the conduit, and bend it over a sharp edge, as soon as the radius of the tube is broken, the tube will easily collapse. There is a certain structural strength to the tube, but once it is compromised, the tube material is pretty soft and malleable. One person that you might check with, is Michael Daly. Recently I saw him post, that he is a structural engineer. He could probably give some good suggestions on real data base. I mostly figure stuff off the seat of my pants, hence the Tinker. My name is a double or triple entendo (sp)! Given enough time, as a practical engineer, I can usually cobble something together! Though it is the sort of stuff you might see on the Red/Green Show. I guess one thing I might ask you though, is how did you come up with the 28" number? Also is your rack a commercial unit, or is it standard Ford issue on Aerostar? As you load the kayak, can you come in at a larger angle to get the bow more up on the vehicle to start. That way the extension would not need to be so long. You would then be standing further out from the vehicle as you lift the stern, lift it higher so that the front does not get pivoted off the front rack, and swing the stern up on the rear rack. Also did you understand about the safety line, which should help keep the bow in place. TnT Sorry Wilf, I answered your second post before I saw the first, will reread and get back to you later, TnT |
#59
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Tink says:
============= I am not sure what you mean by large diameter. We bend conduit all the time with bending tools up to 1". ================= Right, but even to bend 1" pipe, surely you use a "bending device" (my family would disown me for that... both father and brother are electricians and I spent a few summers as an electrician's helper, but am a complete nerd about practical matters... so, I don't recall what that fulcrum thingy is called). Anyway, I'm guessing that the larger diameter pipes cannot be bent, readily, without mechanical assistance. Hence my thought that, if a human can't readily bend it, a 100 pound kayak is not likely to bend it either (even at 50 pounds times, let's say, 30 inches). But, as I say, I'm not the electrician, I'm the geek. Tink says: ================ My name is a double or triple entendo (sp)! Given enough time, as a practical engineer, I can usually cobble something together! Though it is the sort of stuff you might see on the Red/Green Show. =========== And you likely thought ALL Canadians were like Red Green, eh? GRIN Cheers, Wilf |
#60
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BCITORGB wrote:
Hey, you guys have been great! I still don't have my solution, but I think we're getting there. In review, my own particulars a a '94 Ford Aerostar where dents and scratches are not an issue (Hell! It's an Aerostar! Was there ever a cheaper van made?!), no commercial roof rack, just the thing that all Aerostars come with, and a short (5'7"), stocky guy who can carry and horizontal lift the 90 pound kayak to a height of about 4.5' (I've not tried clean-and-jerk... maybe after a few beer). After just two trips, I've just about perfected (and really like) the "front end on the front door" maneuver. BUT, Cyli's got me worried and thinking alternatives. I think Tink has a point re the conduit; after all, it was made to be bent. I went to the hardware store this morning and tried a bit of pressure on the pipe and I was able to put a bit of a bend on it without much effort. I then thought of going one dimension larger for each of the pipes (greater diameter = more difficult to bend, right?). I would have purchased right away had it not been for the price. I need to find me an electrical shop that has "ends" (about 4-6 feet worth of ends) kicking about. As an alternative (and it was something one of you said, I'm sure), I could go very crude and very elemental (if the material strength is up to the task). Tell me what you think... Two approx 7' pieces of 1X4. Place one lengthwise, on the left-hand side of the van, under both roof rack crossbeams. Then, place the other 1X4 under, and at 90 degrees to the first 1X4, with about 3' jutting out over the right-hand side of the van for me to place the kayak on (this piece would be secured, with rope, to the crossbeam to ensure it doesn't slip as the weight of the boat is placed on it). Why 1X4? Because nothing thicker than 1" will fit under the crossbeams and still allow another timber to be placed under it. Question to all you bright guys: will the 1X4 be strong enough to hold the kayak? Cheers, Wilf I think you are right, we are getting there. Starting with your roof rack, it is held on to the top of the van with sheet metal screws, and kf you look carefully you will find a "Do Not Exceed" label, which refers to the Max weight the rack can support. Most are in the range of 100 lbs. This is somewhat misleading because as you are driving down the road you could easily have several hundred pounds of wind resistance trying to take the rack right off the top of the car. This happens every year here, we will read an article in the news about someone losing their roof rack with Kayaks still attached, as they are driving down the road. Happens with skis as well, and typically skis would weigh much less than 100 lbs. For the record, put your skis on the rack with them pointing to the rear. Again typically, it is when the rack gets hit by a gust of wind as you are driving down the highway, that the load limit will be exceded. The carnage that results is not pretty, especially if it is your kayak, vehicle, or friends in the following car that meet your flying load up close and personal. There was a recent thread here or on RBP about how to properly tie your boat on top of car. Basically, you need to use lines tied to bow and stern, tied to the car structure proper. Like a hitch in back, the front can be more problematic. Anyway check the thread, riverman had some good experience recommedations. Now as far as the need for the extension, it becomes clearer now. The standard rack is inset in from the edge of the roof. Also being 57" precludes you just lifting the boat on top of van. I am 74", and take some things for granted. But then you can get into a smaller boat and be comfortable. I get into my Overflow, which is one of the bigger WW boats, and it becomes a squirt boat or submarine. To say nothing about the fact that my feet are all scrunched up. I was reading that Wilko is 80" if I read it right, so I don't know how he does it. Will have to ask him. Anyway, back to your rack, I would look into using a 2x4, U-bolted on top of the existing rack to the side runners, and allow the 2x4 to extend out beyond the side of the van. You could also use 3/4 in galvanized pipe that would resist the salt water better. The ends would be threaded so that you can install end caps. You would not have either of these extending beyond the side of the van further than 4". But if they extended that far, you may be able to hook the end of the boat on that. If not you may still have to work on an extention, but this would give you a base to mount the extention on. See what you think of this, TnT |
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