I have a question about yarder undercarrages. Which ones used the shermain tank for the undercarrage? thanks. If their are not too many does anyone know what the total weight of the yarders weighed?
i believe skagit uses the tank undercarriage as for weight im not sure id have to look in our service manual we run the wheeled unit
Don't recall Madill using a whole tank undercarriage on 09 yarders. We brought in fabricated carriers from 2 different suppliers using surplus military diffs, final drives, trans, bogies, idlers & tracks. The early 071s were on a cut down military undercarrage. I think they were a bren gun carrier but not positive. Later 071 units used a fabricated carreer with military running gear. Also built a half dozen small yarders for Bazil that were on military carriers but I can't recall what the designation was. We used other carriers on occasion Terex ,cat, rubber tired log trucks & skidders but they were mostly 1 or 2 off or special order customer supplied units . Early spars (before I started there) were mostly on old log trucks and military surplus rubber tired tank retreivers. When we got into the swing yarders, loaders, 171 and later models the carriers were fabricated inhouse. I retired 10 years ago so they may have bought carriers for some models after that but I don't think so. I might be able to dig up some weights and military info in a day or so. Regards D.D.
A little background. http://www.traxxon.com/about.html http://www.morpac.com/about/history.shtml Regards D.D.
I believe the Washington 98 Skylok had a Sherman Tank undercarriage.
I think most of the manufacturers bought the same tank carriers. I remember both the Madill 009 and the Tyee K-166 had identical carriers, the "Napco Spar Carrier". Skagit used Pak-Trak carriers. As DD says, they aren't really tank carriers, but are made from tank parts. The Napco carrier was wider and longer than a Sherman tank, and the return rollers were in different locations. The 009 on M4A3 Napco carrier weighed about 60t. When you consider that the M4 suspension was designed to support about 30t..... Most of the ones I've seen have broken springs. I'm pretty sure that the flimsy Bren Carrier was never used to hold a yarder, it would never hold up. Many early Madill spars were on M6 high speed tractors, even had the original military cab to drive them from. Other military carriers used in logging were the M4 High Speed tractor, built by Allis-Chalmers. They mounted tank drills on those. Indeed, the first tank drill was an almost stock M4 HS tractor with a compressor on the deck, and a drill boom on the front. Chapman Motor and Machine Shop in Vancouver used IHC M5 HS tractors to build their "Drilmobile". The Madill 071 used M4 Sherman components, but they called that carrier the "M32". The M32 was the tank recovery version of the M4.
Not to nitpick but I think you are referring to a Washington 78. Both the 78-40 and the 78A had Sherman M4A3 undercarriage. They utilized the front diff and Sherman trans still attached to the front glacis. If I recall, the yarders weighed about 10 ton more than a Sherman tank so there were lots of problems. They just used brakes to steer, an air control for each side, so traveling slow and steering required the outside track to power around the one that was stopped. Then one of the phony connectors popped off and there you sat. Putting the track back on. When we ran chokers the chaser would amuse himself by banging the connectors back in place and tightening the wedge bolts. The tracks still broke and came off the sprocket and just generally drove you nuts. As my father said; Tanks were made to go to war. They weren't made to come back.
Not to nitpick but I think you are referring to a Washington 78. Both the 78-40 and the 78A had Sherman M4A3 undercarriage. They utilized the front diff and Sherman trans still attached to the front glacis. If I recall, the yarders weighed about 10 ton more than a Sherman tank so there were lots of problems. They just used brakes to steer, an air control for each side, so traveling slow and steering required the outside track to power around the one that was stopped. Then one of the phony connectors popped off and there you sat. Putting the track back on. When we ran chokers the chaser would amuse himself by banging the connectors back in place and tightening the wedge bolts. The tracks still broke and came off the sprocket and just generally drove you nuts. As my father said; Tanks were made to go to war. They weren't made to come back.
Long before my time, one of the chokermen got wiped out when an end connector flew off. Hit him "right where it hurts" as they say. I often wonder if the poor fellow ever had kids. The same setup worked fine on drills, though, and they often drove for very long distances. Of course, drills weighed a lot less than a yarder. You're never supposed to let one track stop completely on turns, either. You have to let it creep a bit.
Yeah, I know you're not supposed to let a track stop but the steering controls weren't exactly designed with finesse in mind. On a road change you had to keep track of the haulback and not let it run too slack, keep track of at least one guyline and not get tangled up in that and keep the damn machine from falling off the mountain. Delicate steering maneuvers was not in the forefront of my mind.