Ark Sports Keel Swimrun Pull Buoy Review

Welcome to our second Low Tide Boyz swrimrun gear review show! This week we are reviewing the Ark Sports Keel Pull Buoy. This review was co-hosted by our friends at Swimrun Labs and we think that you will enjoy this review as we left no stone unturned for this one.

We first learned about the Keel while researching swimrun brands to interview for show and quickly became obsessed with this pull buoy once we bought one a put it through its paces. Ark Sports is a great company that we are really rooting for. If you want to learn more about Ark Sports, check out Episode 7 on our podcast where we interview the co-founder of Ark Sports, Christofer Sundberg. 

The Pull Buoy

By way of introduction, Ötillö rules state that the maximum size that a pull buoy can be to be “legal” for any race is 32 cm x 30 cm x 15 cm. You can even use more than one pull buoy but the total size needs to be the same.

The Ark Sports Keel Pull Buoy comes in at 28 cm x 26 cm x 12 cm. It costs 45 Euros or 50 dollars plus shipping to the U.S. from Sweden. (Ark Sports is currently working on setting up U.S. distribution so the shipping costs will come down in the near future.)

According to the Ark Sports website, the Keel was developed and optimized by the world’s best swimrun athletes and the swimrun community. Its distinctive shape claims to minimize drag and maximize floatation in order for you to move as fast as possible through water. 

The pull buoy is made of EVA foam provides massive floatation with a rating of 46.1 Newtons. (The force of gravity on Planet Earth is only 9.8 Newtons.) Needless to say…this pull buoy really floats!

The Test

We all tested the buoy extensively in training and raced with the Keel.

The Swim Review 

Have we mentioned that this pull buoy is super buoyant? So buoyant that you want to be careful in the water because if you’re not bracing yourself, you could flip over in the water. The Low Tide Boyz tested the Keel with other pull buoys in the pool it was pretty clear that the Keel was faster than the Ark Sports Pontoon, the Roka Pro Swim pull buoy and a TYR Swim Float buoy by about 5 seconds per 100 yards (this was not a super scientific study). 

The ladies of Swimrun Labs also put the Keel to the test in a much more controlled trial…that took five days…where they tested 4 types of pull buoys and 1 calf flotation device and found that the Keel was the fastest option. (You can see the results of their study here.) They also found that the Keel was a great leveling agent because it put you in an optimal position for swimming. They experienced some chaffing from the shape of the buoy and the girth of the buoy did require some adductor work to keep the buoy in place. This appeared to be mitigated by using the lasso system to keep the pull buoy in place.

The Transition Review

Swim to Run: 

This was mostly a non-issue with the Keel. Due to the massive floatation we all recommended making sure your bracing yourself as you come out of the water because the Keel will explode out of the water to the surface and that can be interesting if you’re not ready for it. The shape of the buoy was also conducive to placing it on the hip or back depending on a swimrunner’s preference. 

Run to Swim: 

This transition was a bit more complicated. Given the buoyancy of the Keel, it was important to make sure that we were ready to enter the water and start swimming because if not the pull buoy would affect entry into the water. In effect, you have to drown the pull buoy to place it between your thighs if you already waded into the water before being set to swim. Getting horizontal immediately is the best way to get going without having the buoyancy affect you. One point of note is that since the pull buoy is asymmetrical you want to make sure that it’s point the right direction.

The big zoom out is to get to know how the pull buoy acts in the water because it requires a bit of practice to understand how it works.

The Run Review

Running with the Keel takes some forethought. If you’re using the thigh attachment method, it could cause problems on really technical trails getting caught on branches and brush. The lasso/back method resolves that problem, but It takes some getting used to as well. The material of the pull buoy doesn’t slide around and stays in place which is nice.

Low Tide Boyz’z Rankings

Chipper: 4.5 Pull Buoys

Chipper thinks that the Keel is the gold standard of swimrun pull buoys. It looks good and it durable. He docked some points for the cost and for training with the Keel to make sure that you know how to wield it by the time race day comes around.

Chris: 4.5 Pull Buoys

Chris loved the Keel but docked some points for the cost and the fit. It’s not as comfortable as it could be due to the design. That being said, this pull buoy does make you faster. Similar to how the Nike 4% running shoes essentially make you faster (if you know how to run in them) over the marathon distance due to the technology on board, the Keel pull buoy will make you faster in the water. 

Swimrun Labs’s Rankings

Annie: 4.5 Pull Buoys

Annie thought that the Keel is a super powerful pull buoy, that looks cool and increases performance. She docked it .5 pull buoys because of those slightly overdesigned elements that could lead to some discomfort for certain body types.

Brooke: 4 Pull Buoys

Brooke agreed with Annie’s take on the Keel. She arrived at 4 pull buoys by docking .5 pull buoy lost for being overdesigned and another .5 for the cost of the Keel. It’s a little cost prohibitive for people getting first into swimrun when you include shipping from Sweden. All that being said, the performance gains offered by the Keel in the water are undeniable.

 Overall Impressions

Overall, we would definitely recommend the Arksports Keel Pull Buoy. It’s pricey but it checks off all the boxes for what a swimrun pull buoy should provide. While it might be slightly overdesigned and not as comfortable as it could be, it’s still an amazing piece of swimming technology. Not only will it literally make you faster in the water, you’re supporting a great brand that is synonymous with the sport of swimrun.