Watertight enclosure

Hey Rusty,

I need to get at least one of the watertight enclosures on hand ASAP to continue our ROV build. If the Blue Robotics enclosure won’t be available for a while, I’ll need to get one somewhere else…I’d even be willing to buy a prototype…I just don’t have time to build one from scratch.

Any thoughts? Need some info as soon as possible.

Semper Fi,

Mark Hendricks


Please see my email response. For others reading this, we will have a watertight enclosure available for sale in the near future. It was originally designed for our BlueROV but will be sold as a separate product. Stay tuned!


Hey Rusty,

I would be very interested in getting an enclosure for my ROV build when it comes out, but for now, could you email/post the size of the enclosure so that I can know if it fits my design, or if I should try to make my own.




The enclosure for the BlueROV is about 12" long with 4" inner diameter and 4.5" outer diameter. We’ve got a couple available besides the ones for the BlueROV so let me know if you are interested in trying it out.




4" is too big for my purposes, as all i need is enough width to fit an arduino/raspberry pi sideways, which should be 2.1/2", with .3" clearance total, so that I can make a modular control system, and have enough vertical height to use the pins. what’s the smallest volume enclosure that you have that has an inner diameter greater than 2.5" that is at least 8.5" long? However, if you have something closer to those specs, so that I dont need ~10 kg to rectify the weight and get it to a neutral buoyancy, I would be absolutely ecstatic, as I have seen people have lots of problems with some enclosures, so hopefully these might be more reliable.

10 kg to make it neutral? What is it made from? My Aluminum enclosure with an arduino, BasicESC, 4000mAH battery and a few other toys is just about 30 grams negative. It is the same size as Rusty’s.


Battery and the aluminum make a big difference, assuming the acrylic tube is 2.7, excluding everything I am putting inside, it would take 10 kg to make it neutral. Are you sure its 100x3000 mm?

I am using Schedule 40 pipe and 4.5" round stock to make the caps on the end. Yeah … pretty sure about the dimensions.


Quite surprising that it needs so little extra weight, somehow, you must have filled it with enough gear to weigh 12.7 kg, which is the neutral point for a pipe of that size. Congratulations on getting it so close!

I am really confused with your conversions. I have a 4.5" round x 12" long cylinder displacing about 191 cubic inches of seawater. That equates to a weight displacement of 7.066 pounds or 3.205 kilograms.

Where are you coming up with 12.7 kg?


I agree with Harold that the total displacement of our container is about 7 lb or 3.2 kg. It weighs about 2.7 lb or 1.2 kg in air so you’d have to add 4.3 lb or about 2 kg of weight to achieve neutral buoyancy. A smaller enclosure would require significantly less.

Harold is building his enclosure from steel so it is much heavier.

We don’t have any other sizes yet, unfortunately, however you can cut ours to a shorter length.



Rusty, I decided to go with 6061-T6. The blasted weight of 316SS was just to much. I will am going with anodize coating with phosphor bronze helicoils and I am still debating on what metal I will settle for with the screws. Was giving serious consideration to 17-4 PH.

My end caps weight almost as much as the pipe itself. 4.5" round adds up pretty darn quick.


Yeah, I redid the calculations now and realized that in my previous sleep deprived state, I forgot to change the diameter to a radius. Sorry. That said, I think that that enclosure looks a lot more interesting now that I don’t have to add so much weight. I’ll do a few cads and see if 4 inches isn’t too much. Here’s to hoping.


Good. In our experience it’s always better to have more space. Even if you are just using a Raspberry Pi or Arduino it’s the USB connectors and other wires that end up taking a lot of space. We started with a 3" ID enclosure and it was a pain to fit things.


Olli, I totally agree with Rusty. Having extra space is not a bad thing at all. You can always make spacer pieces to “stack” your items. I don’t think there are going to be any thermal issues to worry about in the water … assuming that items like the battery packs (when draining at serious current levels can get HOT) will cause issues with other items … but you never know.

We launched a balloon up twenty miles and everyone was concerned that our payload was going to freeze, I was concerned it was going to burn up. I was called the old crazy dude … Needless to say, when the package came down … we had to wait for almost an hour to open some of the electronics because the heat from the batteries had gotten everything really stinking hot!