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Special math for boat owners

Sooner or later, on every covered boat, the same question keeps coming up. Will this item fit through that hatch?

This hatch keeps out water. And half the stuff you need to put in there.

So the investigative call we got a couple of weeks ago wasn’t surprising. “That commuter bike that folds down to 35″ x 30″ x 15″… will it fit into something 29 inches by 29 inches?”

Once we identified that the “something” was a boat hatch, the possibilities opened up, because then the answer was an easy Yes. Here’s why.

If you put something diagonally through a square, it’s not the side that matters, but the hypotenuse. So multiply A by the square root of 2, or about 1.4.

That 29″ side limitation? When the bike goes in an angle, it’s more 29 x 1.4, or a luxurious 41 inches…assuming the bike is completely flat, which it’s not.

OK, we needed to build a model of this. We needed a 29″ boat hatch in our shop.

29" on a side

Our pasteboard “hatch” needed to be a square, 29″ on a side.

Now for the actual test with a real folded 702 commuter bike…

What this little test means.


It was a simple demonstration, but it means a lot.

If you’re a boat owner, this means you can have a full-size bike for hauling provisions, visiting town, and exploring, and then store it away conveniently below deck (And yes, this bike does come with a free cover).

Bikes in Carry Bag

If you’re an RV owner, that cubbyhole that now has other stuff strewn in it can also carry your transportation for getting around the campground, exploring, and parking in town without looking for RV-sized parking spots.

If you’re a private pilot, you’re familiar with small hatches too. Ever want to put a bike in there?

And to finish off with a math theme…


You may have noticed some extra wiggle room in there during the test. A 29″ square isn’t the minimum size, just what was asked of us. What is the minimum?

If the bike were completely flat when folded, then we could solve for the side lengths using the bike height of 30″, divided by the square root of two, for a minimum side length of 21.5″. But the bike isn’t flat. With the front wheel removed, the rest of the bike is 10″ wide at the widest point. So it’s like passing a 10″ rectangle–no, wait, a trapezoid–through a square…

Maybe it’s time to step away from the complex math for this one…

Clearly, this answer is going to require professional expertise. What’s the smallest hatch/cubbyhole/hold/trunk you’ve put your bike into?

All I know for sure is that it fits in a Smart Car.

And it’s on sale now

DF-702 Black Bike Open

See you out on a CHANGE bike!

Bob Forgrave's Signature

Bob Forgrave is president of Flatbike, an
ecommerce company offering full-size folding bikes
and kits to make any bike take up half the space.


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