AirMattressBoat Take Two- in the Charles!!!

AirMattressBoat Adventure, Take Two! This time, in the Charles. It was a nice day out and not too windy in the morning so I decided to do a boating adventure to test out her capabilities. See the previous adventure here.


The air mattress boat is simple: HackMIT air mattress, lower unit from the cruft shelf, scooter motor, 3s26p from the loading dock, homemade mount, and good ol’ rachet straps. 3s, 26p of 2200mah cells, thats 58 Ah. 650 Wh.

I carried all the supplies to the esplanade. Very nice to be able to carry your water craft.


Assembled and ready to head off! Assembly took about 15 mins, mostly pumping up the air mattress. I brought the pump with me.


And off we went! The boat was actually faster than I remembered and I cleared the Harvard bridge pretty quick.


The trusty brushed scooter motor with on/off switch, no brushless commutator current controlled complexities here. She rattles but she pushes guud. Boston skyline in the background!!



The bridge.


Despite a strong crosswind and slight headwind, I managed to make a pretty good pace. I calculated my pace to be a moderate 2.1 mph.


Cambridge skyline, Mass Ave bridge, Boston skyline, and moter.


took a little shade break under the BU rail bridge.


Playing with the big boys!


The BU bridge. At this point the southerly wind picked up a bit, and the river turned to the north. This meant that I had a strong tailwind and so I really clipped.


The “5 mile run from theta chi” bridge in the distance, which I chose as a turnaround point.


The “micro center is near” Shell sign:


The BU (or Northeastern?) high rise dorms.


Sketchy panorama of the turnaround bridge.


I averaged 2.4 mph from the BU bridge to the turnaround bridge due to the tailwind. The total distance one way was 2.06 miles, and I averaged 2.22 mph.

Some plebians.


I got some great looks from these guys. They were like “huh??”


The return trip upwind was a bit slower due to the headwind but not too bad. The return trip was actually quite social. I ran into many kayakers and paddle boarders who wanted the deets on my sick ride.


Ran into a couple chill dudes in kayaks outside of BU. They asked if the air mattress was comfortable to which I said “duh it is an air mattress”. A floating air mattress is a cross between an air bed and a water bed so really how bad can it be. They also asked if it was losing any air and I told them that yeah I was sitting a little lower than when I started (lol).




I discovered a very comfortable way to ride. I adjusted the motor to turn slightly to the right and dragged my feet in the water on the left. By varying the depth my feet were in the water, I could easily turn the vehicle.


The Boston skyline was quite beautiful.



Beautiful pano of the bridge!


The great dome!


The dock. Heading home. Set out at 11:20, got back at 1:10.


Docked!! Total time afloat: 1 hour, 50 mins.


Total distance traveled: 4.22 miles. Average speed: Exactly 2.3mph.

travel annotated

I let everything dry for a bit before packing up. Overall, a complete success.


Again, this trip was a complete success! The battery dropped from 12.00 to 11.52, from 4 volts/cell to 3.84 volts/cell. Based on this, I’d estimate that this battery would be good for 5 hours of continuous use, for an ultimate range of 11.5 miles. Next time, longer adventure!