Most vehicles on the road today are multipurpose devices. Your four-door truck can do the school run and haul lumber, while your SUV can tow a camper or take you touring off-road. In contrast, jinkers are single-purpose. These Australian oddities are built to do one thing and do it well. You’ll only find them in one place on Earth.
The jinker is an ungainly thing at first glance. They look like a regular vehicle on stilts. Indeed, that is precisely the idea.
The creation of the jinker was all down to the peculiarity of the Gulf of St Vincent, and some good old-fashioned Australian ingenuity. Let’s take a look at these unique, hand-built machines, and learn just how they make life easier on this remote stretch of Aussie coast.
https://www.instagram.com/p/C5P6Ttdu4-P/
It’s A Long Way To The Slop
The jinker is primarily found in just two locations along the South Australian coastline. Port Parham claims the jinker as a local invention, but they’ve also been spotted up north at Port Germain. Both towns share something in common—an incredibly flat sea floor paired with six-foot tidal swings. I happened across the town of Parham many years ago when I was arranging a robot mission, and I was floored by the uniqueness of the landscape.
Head out to the beach at Port Parham, and you’ll be struck by just how weird the geography really is. At high tide, the water’s right there with you. Come back at low tide, step out on the sand, and you won’t reach the ocean for a full mile. The seabed is so flat that you can walk for 20 minutes without hitting the water. You’ll tread in just a few puddles left behind from the high tide.
It’s a truly strange landscape—and one that makes launching boats a real pain. There’s no way to build a traditional boat ramp because the sea floor doesn’t drop away fast enough. Even if you did launch your boat on the water at high tide, you’d be screwed when you came back later. Why? Because at low tide, the edge of the water is a full mile further away. You’d either have to time your entrance and exit from the water perfectly with the high tide, or you’d be screwed. With high tides around 12 hours apart, it’s not really practical.
The jinker was the solution to this thorny problem. It’s a vehicle specifically designed for launching boats on this weird bit of coastline. Jinkers are designed for towing boats into the water and nothing else. They keep the engine high and dry, and the driver to boot. These are homebuilt contraptions, of which less than 100 have likely ever been built.
Launching a boat with a jinker is much easier than using a boat ramp. A jinker driver might leave their home a few hundred yards from the shore, towing their boat on a trailer. They’ll head out into the water at a depth of around 3 feet or so, as the tide is coming in. They’ll park the jinker, launch the boat from the trailer on the back, and go fishing. They’ll then come back to the same point around five or six hours later, catching the tide at roughly the same depth on the way out. They can park their boat right on the trailer and then drive the jinker back home.
Jinkers launching boats during high tide at Port Parham.
Jinkers perform their role with surprising mechanical simplicity. They typically run straight-sixes from Aussie cars, most relying on old Holdens and Hemi engines. Drive is sent via the transmission and a horizontal driveshaft to a vertically-mounted differential, which is locked to act as a 90-degree angle drive. This differential then sends power down to a second live-axle diff at the bottom of the jinker, which runs the rear wheels.
This two-differential design has two benefits. Firstly, it neatly transfers drive from the high-mount engine to the low-mounted rear wheels. Secondly, it provides an additional gear reduction which gives the jinker more torque at the wheels.
Relying on old carby engines keeps the jinkers simple. Small fuel tanks made out of jerry cans are typical. Radiator fans are usually fitted as jinkers run quite slowly. Most jinkers have minimal electronics—just enough to run the starter motor and ignition system, and maybe a gauge or two for keeping an eye on vital temperatures. Both automatic and manual gearboxes have been used on jinkers, though there’s not really much call for shifting into high gear. Jinkers are low-speed craft that rely on torque to tow their loads.
Nifty engineering solutions abound on these vehicles. Several jinkers use disc brakes mounted high on the 90-degree differential instead of on the wheels directly. This keeps the disc brake components out of the water, greatly reducing corrosion and thus the amount of maintenance required. Each jinker also has its own unique way of hooking up the steering wheel to the front wheels. I saw one using a full-sized tail shaft in this role.
Many of the jinkers have tow balls mounted front and rear for more flexibility. Meanwhile, suspension is usually limited to a set of springs on the front wheels, if present at all. It’s simply not necessary when running on the soft sand at low speeds.
Better Than The Rest
Jinkers do their job far better than a traditional four-wheel-drive could. Most capable off-road trucks and SUVs would be sucking down water in the kinds of depths jinkers happily operate in. Even if you had a proper snorkel set up, you’d still end up flooding the cabin with seawater most of the time. And your differential. And your battery. Regular off-roaders simply aren’t designed to stay submerged; they’re built for fording a small stream at best.
It’s also one thing to drive out into a few feet of water, and another thing entirely to leave your vehicle sitting in it all day. A typical off-roader would end up hydrolocked or simply drift away as the tide came in further. Jinkers are designed to sit high enough that they can be parked in the water with no risk. Even at high tide, the sea level never reaches the engine. Plus, their open steel frames don’t displace much water, so jinkers don’t float.
Being single-purpose vehicles, jinkers are typically registered as “restricted miscellaneous vehicles” in South Australia. This is a category for vehicles like golf buggies or ATVs which may occasionally need to use public roads. It allows the jinkers to be driven from an owner’s house to the seabed and back again as needed. It’s also more affordable than registering a road-going vehicle to do the same job.
You could never hope to buy a jinker from a large company. The population of Port Parham and Port Germain combined is under 500 people. The market simply isn’t there.
Instead, the jinkers are a great example of local builders engineering vehicles to suit their own needs. They’re highly specialized, highly unique, and highly cool. And, you know, just high in general! Which is kind of the whole point.
I was thoroughly thrilled to see them out on the sand. The town doesn’t have its own tourism bureau, but the local Port Parham Sports and Social Club will gladly sell you a beer and tell you all about these Galapagos Tortoises of the automotive realm. I can confirm it’s well worth dropping in if you find yourself in the area!
Image credits: Lewin Day
Special thanks to Laurence Rogers for IDing the engines on these wonderous craft.
This is awesome! Never knew about these. Pretty clever solution to a very unique geographic situation.
They probably have to change out the diff fluid and wheel bearing grease on the bits that actually are in the water though, right?
We had a similar water problem on some of our industrial gearboxes and wound up switching from oil to water-shedding grease. Each time the equipment stopped the water would settle out into a drain.
Probably a headache for a vehicle that’s used intermittently, but it successfully kept away submersion issues. Having dunked my truck axles a few times I don’t trust wheel seals to keep water away from the diff gears when submerged. Certainly not for years on end like the grease did.
I imagine wheel bearing maintenance is a pretty regular thing, yeah. Not sure how well sealed the diffs are but I spotted a very extended diff breather line on one to keep the salt water out.
This looks like a simpler and cheaper alternative to the waterproofed tractors used for lifeboat launching in the UK.
You’d have to overfill the heck out of the upper diff gearbox to keep the pinion lubricated running sideways like that. And you’d want to add a fill plug on the cover to facilitate that. Little details like that are interesting.
Those are really cool!
We should show this to Elon Musk – then he would be busy making the roadster be better than the jinkers, too.
Oil changes should be a breeze, on these . . . 😉
The big brother to the jinker lives on the Devon coast, taking guests to the hotel on Burgh Island: https://www.burghisland.com/about-us/sea-tractor/
Here’s an older version seen in this Pathe film clip from 1964: https://youtu.be/rS69xxbABSI?si=p4ujiVxX1aY6f-w-
And 1938: https://youtu.be/2CEuRiLNRPg?si=uJS9YIZle6-0W_Dt
There’s another one in South Sands, in Devon, that takes passengers out to a ferry.
Had the same thing in Rocky Point (Puerto Peñasco), Mexico. The slope of some of the beaches you can walk out like a mile at low tide. High tide and you can walk out a 100 yards and still be in knee deep water
haha, same experience! it’s quite odd the first time you’re out there.
Now, the only relevant matter on this topic: racing. I want to see them late-breaking into an apex, wheel to wheel under the water.
I want a Jinker racing series
Now, I’m pretty certain that the first jinker race was held right after the second unit was built. I’ve no proof, nor doubts. But a sanctioned series would be phenomenal, even by Australian levels of awesomeness.
Relay race: LeMans start from the bar to the jinkers. Jinkers launch boats, boats reach buoy #1,designated swimmers race to buoy #2 and back to boats, back to jinkers, back to start line. Somewhere in there beers must be chugged, maybe a beer bong from the deck of the jinker to the boat.
and boomerangs…
This is fucking brilliant. It’s almost on par with Olimpic kangaroos riding.
Aussie Autopians must be taking notes.
Wow. What an awesome solution to an a very niche case problem. I wonder if the salt or constant sun is worse for tire breakdown.
Id guess the sun. I don’t think salt hurts rubber, UV and oxidation is what really does it.
This is an amazing, out of the box solution to a very unique problem and just when I think I couldn’t get any more unique they go and fit a brake disk to the other half of the high differential. Amazing.
my favorite feature as well.
Mad Max runs deep in the Australian consciousness
Just don’t look right without some sort of weapon mounted on the front though.
Just don’t look right without some sort of …person… mounted on the front though.
Very cool article Lewin! The Autopian is the best, the weird knowledge I gain here on an otherwise mundane work day is outstanding!
Neat.
Can someone explain the brake over the diff? the yellow pic labelled “The differential-as-90-degree-drive setup allows a single rotor and caliper to brake both rear wheels. It also keeps the brake assembly clear of the water and sand below.”
Wouldn’t you have to lock the upper output to use the diff as a 90 degree, but there’s the brake there so it moves.
Oh got it. The diff is locked.
Sounds like you already got it, but if they had just made the top end stationary they’d lose a lot of the gear reduction, so the real solution is to lock the diff like in an off-roader or drift car, likely by welding the diff gears internally. That way there’s effectively a solid axle attached straight to the ring gear, and the brake can interface directly with the output. I imagine this is also great for serviceability, as the brake is right on top and can be accessed without taking the shaft off.
Thank you.
“they’d lose a lot of the gear reduction”. I hadn’t realized that bit.
I’m a software guy by trade and I do not have good intuition about mechanical systems. I’ve watched https://www.youtube.com/watch?v=yYAw79386WI probably 6 times and it’s clear I still don’t quite get it.
Think about it this way: If the ring gear is stationary and one side spins forward, the other spins backwards at the same speed. the average of the outputs here is zero. This maintains when the ring gear is spinning, such that
[ Speed(left) + Speed(right) ] / 2 = Speed(ring). If the speed of one of the outputs is zero, then
[ 0 + Speed(right) ] / 2 = Speed (ring)
Cancel the /2 and you get:
Speed(right) = 2 * Speed(ring)
This would cause gear reduction to be halved, as the output spins at twice the ring gear’s speed.
I figured algebra would be the ideal universal language between software and mechanical engineering.
That is in fact very helpful. Thinking about it that way helped me understand what I’m seeing in differential demoes and cut away models.
So thanks again.
Well there you go. I HAVE found myself driving past the turnoffs for Port Germain and Port Parham before. I’ve never wondered whether there was anything there worth looking at. I’m going to have to try to spot one of these giraffe mobiles in the wild next time!
I enjoyed this more than I expected to 🙂
If the right tool for the job doesn’t exist, make it. Wonderful stuff.
Lewin, what a great article man! Any idea what the etymology of the word “jinker” might be?
Thank you!
I believe “jinker” is a term often used for “boat trailer” or “boat launcher.”
I see it used sometimes on ads for boat trailers.
A truly unique solution to a truly unique problem. These rock and if I somehow find myself near Adelaide (unlikely but you never know) I’ll be on the lookout for these.
As an engineer with an engineering degree, I can confidently say that some of the best engineering comes from people who’ve never been to engineering school. These things are ingenious and cool. I love the use of a second differential with a brake on one end.
If I’m ever in that part of the world, I’m stopping by just to ask a confused local to give me a ride on one of these.
100% agree on the engineering point. I went to Michigan Tech, but some of the coolest mechanical engineering I’ve seen is from degree-less Yoopers. When people live in remote areas and operate on limited budgets, miracles happen!
How clever! My first thought would be to try to put skis/runners on an airboat, but I suppose this less suicidal kind of crazy works too.
Or some kind of home-built, mad Max Ekranoplan?
I was thinking Gator McClusky vs Max Rockatansky, a fight-then-team-up movie 40 years too late!
funnily enough Parham would be a great spot for a hovercraft
This is almost the perfect zombie apocalypse vehicle…
Wonderful stuff, Lewin. When I first saw the article, I thought it was going to involve strapping your enemies to the front of your vehicle in order to intimidate their friends in the town with the bus-gate.
My first thought too.
Boat launching is on the weekends.
Enemies tied to the front, driving around, intimidating everyone, faces painted, screaming war boys… That’s their day job.
“Just walk away and give us the gas”
Autopian at it’s finest, thanks for this article. I can’t help but wonder about two towns with the name “Port” that, given the nature of the beast, could never have an actual port. Is that Aussie humor?
According to Wiki, the towns were indeed formerly (small) ports. Mostly serving the city of Adelaide.
Rural PA has a number of towns with names like Whateversport. Many of them have, at best, a stream flowing through.
Regional town-naming is kind of fascinating. In some parts of the US, towns ending in some form of “boro” are a dime a dozen. One of my favorite Interstate big green signs says “Asheville, Nashville, Knoxville”. In drier climates out west there’s a ton of “Springs”, which makes sense.
And then there’s the boring-ass suburbs. Around here, we have a Forest Park and a Park Forest. We also have a Forest Lake and a Lake Forest. And a million towns with “Park” at the end.
Unrelated, but I’m reminded of the first five seconds of this clip.
What really grinds my gears are those names that are straight up ripoffs from far more well-known locales, such as:
Canton, OH
Syracuse, NY
Rome, NY
London, Ont., Canada
Manhattan, PA
Manhattan, KS
Brooklyn Park, MN (OK this one at least tried)
I’d give Cambridge MA a pass. It being home to MIT and Harvard is worthy of the name.
Like the original settlers of New England naming everything after the places in Olde England that they had just left.
and the province of Ontario, featuring sites such as London and Waterloo
What’s worse, this is not in any way a clue as to where in the US you live.
Not to mention all the Whatever Townships that don’t have single ship.
Nope – people used to actually ship wheat out of Parham (and other stuff out of Germain). It was a real pain in the ass with the tides.
These are some seriously cool contraptions, I’m glad I can rely on y’all to report on these weird little off-kilter machines. I particularly love how some of them take advantage of the unused stub of the vertical diff to attach the single brake, that must make disc changes a breeze.
I don’t know if they would ever need to change the brake disc in a lifetime, speeds would be so low that you could wear the surface all the way down to the cooling vanes!
I imagine it’s more likely to get frozen and/or rust until it’s unusable due to seawater exposure, especially as the low speeds mean there’s nearly no pad scrubbing to clean up the surface, even more so it it doubles as a parking brake. But you’re right, it’s probably not a frequent maintenance item.