# Problem with sinking **URL:** \ **Category:** General Discussion\ **Created:** [May 1, 2022, 9:38am UTC](https://discuss.bluerobotics.com/t/problem-with-sinking/12058 "2022-05-01T09:38:22Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![ChairmanAlex](https://avatars.discourse-cdn.com/v4/letter/c/91b2a8/32.png) [@ChairmanAlex](https://discuss.bluerobotics.com/u/ChairmanAlex)\ **Post date:** [May 1, 2022, 9:38am UTC](https://discuss.bluerobotics.com/t/problem-with-sinking/12058/1 "2022-05-01T09:38:22Z")
i finished building my ROV…but i have trouble to make it sink under the water. i need help on how i can add up the mass to make it sink…any help will be appreciated since this is my first time to build the rov ---
**Author:** ![EliotBR](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.bluerobotics.com/eliotbr/32/6937_2.png) [@EliotBR](https://discuss.bluerobotics.com/u/EliotBR)\ **Post date:** [May 1, 2022, 11:39pm UTC](https://discuss.bluerobotics.com/t/problem-with-sinking/12058/2 "2022-05-01T23:39:07Z")
Hi @ChairmanAlex, To make something in the water sink you can either - increase weight relative to volume (e.g. add [ballast weight](https://bluerobotics.com/product-category/watertight-enclosures/ballast/)) - reduce volume relative to weight (e.g. use smaller [enclosures](https://bluerobotics.com/product-category/watertight-enclosures/), remove [buoyancy foam](https://bluerobotics.com/product-category/watertight-enclosures/buoyancy/), etc) - apply active forces (e.g. vertical thrusters) If it’s helpful, our [BlueROV2](https://bluerobotics.com/store/rov/bluerov2/) is designed to be slightly positively buoyant, so it floats to the surface when unpowered (which helps with retrieval), but has sufficient vertical thrust capacity that it can easily move downwards when necessary. Our [BlueROV2 Heavy Configuration](https://bluerobotics.com/store/rov/bluerov2-upgrade-kits/brov2-heavy-retrofit-r1-rp/) has two additional vertical thrusters, and also some extra buoyancy foam to compensate for that extra weight, so it’s still slightly positively buoyant by default but has some extra payload capacity if it picks something up, or can move faster vertically when not loaded. * * * By the way, is there a reason this was a private message instead of a public post? Others may benefit from reading the discussion, or be able to contribute to it, so if it’s ok with you I’ll move this over to be public 🙂 ---
**Author:** ![ChairmanAlex](https://avatars.discourse-cdn.com/v4/letter/c/91b2a8/32.png) [@ChairmanAlex](https://discuss.bluerobotics.com/u/ChairmanAlex)\ **Post date:** [May 2, 2022, 1:53am UTC](https://discuss.bluerobotics.com/t/problem-with-sinking/12058/3 "2022-05-02T01:53:01Z")
its ok you can make it public 🤣 ---
**Author:** ![EliotBR](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.bluerobotics.com/eliotbr/32/6937_2.png) [@EliotBR](https://discuss.bluerobotics.com/u/EliotBR)\ **Post date:** [May 2, 2022, 3:41am UTC](https://discuss.bluerobotics.com/t/problem-with-sinking/12058/4 "2022-05-02T03:41:51Z")