D4E1 - STOODLE: a Modular Kickboard That Grows With You

Stoodle is a kickboard that adapts to you.

It was designed for swimmers who have more strength in one arm than the other. A regular kickboard doesn't help with this, it either gives too much support or none at all.

Stoodle uses pool noodle pieces as removable inserts. Add more on the weaker side for extra stability. Remove them one by one as you get better. The board grows with you.

It's made from just four materials: EVA foam, pool noodles, rope, and glue. Cut with scissors, no machines needed. All materials are cheap and available anywhere in the world.

Step 1: The Problem

Step 2: The User

Step 3: Design Requirements

Step 4: Concept Development

Step 5: Materials & Prototyping

Step 6: Testing

Step 7: Final Design

Step 8: How to Build It

Step 9: How to Use It

Step 10: Conclusion

Materials

1. EVA foam sheets (the same material as floor puzzle mats)
2. Pool noodles (PE foam)
3. Rope or cord
4. Contact cement glue
5. A small piece of tape (to stiffen the rope tip, like a shoelace, making it easier to thread through the holes)

Tools

1. Scissors or box cutter
2. Marker or pen
3. A sharp pointed object (such as a thick nail, knitting needle, or screwdriver)
4. Clamps or heavy objects (to press layers together while glue dries)

All materials are cheap and widely available at hardware stores, toy stores, or online. No special equipment needed.

Nicolas is a young swimmer with a muscle imbalance in his right arm. Because of this, he swims crooked, his weaker side gets less support, causing him to drift to one side.

Standard kickboards don't help with this problem. They either support both sides equally or do all the work for the swimmer, meaning the user never actually learns to correct their posture.

We needed something different, a board that supports the weaker side without taking over, and that can be adjusted as the swimmer improves.

Stoodle was designed with Nicolas in mind. Nicolas is a young swimmer who has more strength in one arm than the other. This makes it hard for him to swim in a straight line.

But Nicolas is not alone. Many swimmers, young and old, deal with the same challenge. A stroke, an injury, or a condition from birth can all lead to uneven arm strength.

Stoodle works for anyone who needs a little extra support on one side, and wants to build up their swimming over time.

Before designing, we set a few clear goals for the product:

1. It must support the weaker side without doing all the work
2. The user must still be challenged to swim straighter over time
3. It must be adjustable (more support when needed, less as you improve)
4. It must work for both children and adults
5. It must be cheap and easy to make anywhere in the world
6. No machines or special tools required

These requirements shaped every decision we made throughout the process.

Finding the Right Shape

Before thinking about modularity or progression, we first focused on finding the right board shape. We made many different prototypes using differents sorts of foam, layered foam on top and bottom, a rigid ABS plastic sheet in the middle for stability. Every version had a hand grip hole cut through it so Nicolas could hold the board without anything being strapped to him. This was important: he wanted to be able to let go at any moment.

We also thought carefully about ergonomics. The arm rest was angled slightly so his arm could lean on it comfortably without any sharp edges. We rounded off the front to reduce drag in the water, similar to the hull of a boat.

After many iterations we landed on the final shape, a wide triangle on top for stability, two wide arm rests at the bottom, and a central grip hole.

From Shape to System

Once we had the right shape, the next question was: how do we make this adaptive, affordable, and motivating? We didn't want a board that does everything for Nicolas. We wanted something that supports him while pushing him to improve on his own.

This is where we explored three concept directions.

Concept 1 — Segmented Board

A plastic core with removable EVA foam pieces that click on like lego, color coded by level. We moved away from this because the click connectors required too much precision to make, and the rigid core made it impossible to adapt the board to different body sizes.

Concept 2 — Rollable Mat

A flexible fabric mat with sewn pockets holding foam inserts of different densities. Modular, foldable, and adaptable per zone. We developed this concept far but eventually moved on because sewing elastic openings, wrapping foam in fabric, and producing consistent inserts made the build process too complex.

Concept 3 — Pool Noodle Board

We simplified everything. Slots are cut directly into a middle EVA foam layer. Pool noodle pieces are pushed through the slots and held in place with rope threaded through the EVA layers. No fabric, no complex sewing, no cutting complex inserst, just simple pool noodles, rope, and contact cement glue.

We chose pool noodles because they are cheap, found in almost every swimming pool in the world, skin-friendly, water-resistant, durable, and literally designed to float. Cutting them requires nothing more than a knife.

Adding more noodles on the weaker side gives extra stability. Removing them one by one as the swimmer improves lets the board grow with the user. This became our chosen concept.

Finding the Right Material

Early on we used a rigid insulation-type foam because it was cheap and easy to get. It turned out to be too brittle, cracked under pressure and tore easily, so we quickly moved away from it.

At some point we tried making the board entirely from yoga mat material. This seemed ideal at first because its one single cheap material that everyone knows. But in practice it did not float well enough. So we moved on.

We landed on EVA foam. It floats well, is soft and comfortable against the skin, and slightly compressible, which turned out to be a key advantage. When you push a pool noodle piece into a slot cut through EVA, the foam grips the noodle tightly. No extra fixings needed. It holds, but you can still pull it out when you want to adjust.

We also discovered that EVA foam is widely available in a very practical form. The interlocking puzzle play mats used for children. These come in large flat panels with snap-together joints along the edges. We used these as our main material, making it easy to source in large quantities at low cost almost anywhere in the world.

Building the Prototypes

We built multiple versions of the board, each time refining the shape, the number of slots, and the layer setup. The basic structure stayed the same throughout: solid EVA layers on top and bottom with a middle layer featuring cut-out slots for the pool noodles. Rope threaded through holes in the EVA layers holds the inserts in place. Everything is bonded with contact cement glue, which holds much better than hot glue over time.

We also removed the ABS plastic inner layer we had used in earlier versions. EVA alone turned out to be rigid enough, which meant no more laser cutter and no more hard-to-find ABS plates.

What We Learned

EVA foam is the right material for Stoodle. Pool noodles fit tightly in the slots thanks to the compressibility of EVA. Contact cement holds the layers together reliably. And with no ABS plate needed, the entire board can be built anywhere in the world with scissors, a craft knife, rope, and glue.

What We Tested

We tested the board with Nicolas in the water at LAGO Kortrijk. We focused on two things: does the board help him swim straighter and does it feel comfortable to use.

The wide arm rests give a stable base and the angled surface would keep his arm in a comfortable position.

Nicholas can hold the board naturally without anything strapped to him, and let go whenever he wanted.

Adding more noodles on the weaker side visibly improved his straight line swimming. Removing noodles one by one increased the challenge gradually.

What Could Be Better

Four slots turned out to be too few for fine-grained progression. We want to add more slots so the transition between levels is smoother and more gradual.

The contact cement glue held well. The rope system kept the noodles securely in place during swimming without any coming loose.

Conclusion

Both prototypes performed well in the water. EVA foam floated better and felt more comfortable than the earlier insulation foam. Nicolas did not notice a significant difference between the two EVA versions in the pool.

Stoodle

Stoodle is a layered EVA foam kickboard with removable pool noodle inserts. Made from interlocking EVA puzzle mat panels. The foam is cheap, widely available, and cuttable with scissors or a boxcutter.

Shape

Wide triangular top for stability. Central grip hole so the user holds the board naturally without anything strapped to them. Front edges rounded off to reduce drag. Two pool noodles in the centre stick out as arm support. Two noodles in the wings are inserted at an angle, covering more surface area for extra buoyancy on the sides.

Layer Structure

Four EVA foam layers bonded with contact cement. Top and bottom layers are solid. The middle layers have a rope connection through punched holes, creating the slots that grip the pool noodles from inside.

The Inserts

Pool noodles cut into halves or quarters. Pushed through the slots, sticking out on both sides. The compressibility of EVA grips the noodle tightly. The rope locks everything in place. To remove: simply pull out.

How It Adapts

Add noodles on the weaker side for extra support. Remove them one by one as the swimmer improves. Longest noodles fully loaded = maximum support. Shorter lenght or empty slots = training mode. Works for any swimmer, at any level, at any age.

Step 1: Cut the Board Shape (2 times)

Draw the board shape on your EVA puzzle mat panels using a marker. Cut two identical layers with scissors or a craft knife:

1. Wide triangle on top
2. Central grip hole
3. Rounded front edges

Step 2: Cut the Middle layers (2 times)

For your middle layers

1. a shape that follows the front of the board
2. keeping space on the back and middle so that there is room for the noodles

Make them slightly narrower than your noodle pieces so the foam grips them tightly.

Step 3: Glue the Layers

Apply contact cement to all bonding surfaces. Press the four layers firmly together. Place heavy objects on top while drying.

Step 4: Punch the Rope Holes

Use a scratch awl or nail to punch holes along each slot. Thread rope through and knot them together.

PRO TIP: Wrap tape around the rope tip to thread it easier, like a shoelace.

Step 5: Add the rope

Put the rope trough the holes and knott them together

Step 6: Cut and insert the Noodles

Cut noodles into halves and different lengths. Push each noodle piece through its slot. The EVA grips it, the rope locks it in place.

Adding Support

Push noodle pieces into the slots from below. Add more on the weaker side for extra buoyancy and stability on that side.

Reducing Support

Pull out one noodle at a time or switch them with shorter ones, as the swimmer improves. Less noodles = more challenge.

Correcting Posture

Still drifting to one side? Add an extra noodle on that side to compensate and retrain straight swimming.

The Levels

1. Level 1: all slots full with longest noodles, maximum support
2. Level 2: remove wing noodles or replacing them with shorter ones, less lateral stability
3. Level 3: one or two noodles left
4. Level 4: empty board, swimming independently

What We Made

Stoodle is a modular kickboard for swimmers with uneven arm strength. It adapts to any swimmer, at any level, at any age. Built from EVA foam and pool noodles with scissors, rope, and contact cement. No machines needed.

What We Learned

1. EVA foam is the ideal material: floats well, grips noodles, cheap and available worldwide
2. Pool noodles are the perfect insert: already designed to float, easy to cut, found in every swimming pool
3. Angled wing noodles cover more surface area than straight ones
4. Contact cement holds much better than hot glue over time
5. Less is more: simpler build = more reliable product