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When I build underwater, I start with making the glass walls and ceiling. I then fill the top of the inner-trapped water room so I have a gap of breathing space. Afterwords, I fill in the rest with sand and delete it all to reveal the open space. The process is extremely tedious, and I was wondering if there was any simpler method?

Thanks for reading!

Quote from Master_Buttchin

When I build underwater, I start with making the glass walls and ceiling. I then fill the top of the inner-trapped water room so I have a gap of breathing space. Afterwords, I fill in the rest with sand and delete it all to reveal the open space. The process is extremely tedious, and I was wondering if there was any simpler method?

Thanks for reading!

Hopefully someone has some good ideas.

Just finished my piston door docks yesterday, had to do Redstone wiring under water. Filled in a 4 x 40 x 5 area of water twice. Felt like it took forever and it IS extremely tedious.

They should have a "reverse TnT" where instead of exploding, sponge or some material busts out and falls like sand.

You could place a few in a boxed off area and fill it in more quickly...

Not a GOOD idea, but an idea.

I like that idea, Mr Puma. I always wanted something like cat litter. You can dump it in one spot on the ceiling, and it moves out and removes any water within a certain parameter. It keeps moving out until it reaches X spaces, then it disappears.

Sand or gravel is my favorite filler, since you just have to aim UP and keep mashing LT. Its also a helluva lot easier to break than cobble.

Quote from Master_Buttchin

I like that idea, Mr Puma. I always wanted something like cat litter. You can dump it in one spot on the ceiling, and it moves out and removes any water within a certain parameter. It keeps moving out until it reaches X spaces, then it disappears.

Sand or gravel is my favorite filler, since you just have to aim UP and keep mashing LT. Its also a helluva lot easier to break than cobble.

What do you mean look up and keep hitting LT. For what?

Quote from Puma_SPNKr

What do you mean look up and keep hitting LT. For what?

If you just aim on the ceiling and mash LT, the sand will automatically fall down and keep stacking until it fills itself up to the top. It saves the work of having to move down to reach the lower blocks. This is especially necessary if you're making a high ceiling.

Also, you can try putting sugarcane underwater so that you have a close air pocket when you start to drown. You just need an empty hole next to the sugarcane you placed underwater so the dirt block gets water. Sugar cane actually looks kinda cool underwater...kinda like seaweed

i had the same issue with filling in underwater mine shafts. i also use the sand method..... maybe make a drainage tunnel . will try to find new methods when i build my evil underwater lair

If you have the materials, place TnT blocks. Since all you need to do is hit them once to break them, it makes getting rid of them very easy. As long as your not going to have any levers or pressure plates down with you while your getting rid of the water, you shouldn't have any problems

Quote from KushmanZaTa

If you have the materials, place TnT blocks. Since all you need to do is hit them once to break them, it makes getting rid of them very easy. As long as your not going to have any levers or pressure plates down with you while your getting rid of the water, you shouldn't have any problems

I usually play on peaceful, so gunpowder is kind of a rarity. Also, doesn't water stop TNT from exploding? Either case, It seems the effort in killing the creepers and digging sand up for TNT just isn't as fast as doing the "long" method with filling with sand, and deleting. After-all, you get your sand back.

Quote from mister_blockface

i had the same issue with filling in underwater mine shafts. i also use the sand method..... maybe make a drainage tunnel . will try to find new methods when i build my evil underwater lair

The water wont drain if every block within the body of water's area is a source block. That means every block of space within your underwater build must be filled so that it's cleared of water.

Quote from Master_Buttchin

... I fill in the rest with sand and delete it all to reveal the open space. The process is extremely tedious, and I was wondering if there was any simpler method?

When I build underwater I follow the sea floor and put glass on top then dig the dirt out only once.

But for your method try filling it with sand breaking the first sand block on the ground and placing a torch very fast before the other sand falls to take its place. this will in turn break the entire row of sand while falling.

Quote from Major_MoMSqueal

When I build underwater I follow the sea floor and put glass on top then dig the dirt out only once.

But for your method try filling it with sand breaking the first sand block on the ground and placing a torch very fast before the other sand falls to take its place. this will in turn break the entire row of sand while falling.

Thanks, but I already know of that method. Frankly, its not even breaking the blocks thats so tedious....its having to stop filling in the watery area to grab another breath of air. That includes the amount of time it takes to break a block underwater (if you make a mistake) and the currents that keep pulling you back when you start losing health from drowning. At a certain point of being stuck from drowning, I'll just stop fighting the current and dig a straight hole down so my supplies don't fly all over the place. haha


Actually, I just came up with an idea. Placing a torch in water will delete the water and remove the torch if any other source blocks are adjacent. If you start covering the top area with torches QUICKLY (or with other people) you may be able to clear up some water above for easier working....and the filler blocks already removed themselves!

I haven't actually tested this, but you should be able to place dirt on the very bottom and plant reeds/sugarcane until you reach the ceiling of your base. Then to clear it you just hit the bottom of each one. That should work, right?

If at the bottom of the "filling in area" you make a 3 deep 1 x 1 an place a sign on the entrance to this tunnel, it'll create an air block. So if you shovel from the inside out, it may help during those later stages.


Btw, if you take a bucket you can keep smashing the LT then. If you take from a source block and pour it into another source block it'll essentially destroy itself (obviously). If you can do this quickly enough, from top to bottom, and with some organization, you maybe able to rid yourself of the block duties. You will still need to lay a a full walled perimeter of course.

Quote from iAwesome333

I haven't actually tested this, but you should be able to place dirt on the very bottom and plant reeds/sugarcane until you reach the ceiling of your base. Then to clear it you just hit the bottom of each one. That should work, right?

I haven't tried that method, but I'll go ahead right now.Can't place sugar in a water block. Oh well.

An easy way is to fill the water space up with leaf blocks and then set it on fire afterwards and burn it all away.

Quote from truckergut

An easy way is to fill the water space up with leaf blocks and then set it on fire afterwards and burn it all away.

Thats a good one i have to try it laterinstead of leaving a gap for air make the walls without the ceiling at first and start putting sand at the top block all around the walls, keep filling in with sand from the top and then at last you put the ceiling, now you open a gap and start clearing the sand, but there wont be water anymore so it will be less tedious. And of course you have to cover the gap again so you wont have water filling the inside.


I personally avoid building underwater, but i love doing it inside mountains.

What I do i place all wood blocks down the cover it with glass. Then I dig under till I get back to wood and set it on fire. Easier done that way.

Quote from iAwesome333

I haven't actually tested this, but you should be able to place dirt on the very bottom and plant reeds/sugarcane until you reach the ceiling of your base. Then to clear it you just hit the bottom of each one. That should work, right?

This method is very possible. The only issue is that the sugar cane's dirt block must have a side exposed ot water. Although its all underwater, the sugar cane acts as an airpocket, so the top of the dirt block its placed on is actually air. You need one of the sides of that dirt block exposed to water.

You can try making an alternating 2 block high pyramid of rows across the room underwater. Heres a rough text sketch, as though you're looking from the side:





. Xs are blocks of dirt. _s are blocks of water which will be directly contacting the outer Xs. You're leaving the _s to fill last, but may fill ones you've already passed as you make your way across the pyramids. Moving to the right, you would plant a sugar cane on the first two Xs on top. Delete them. Now add more sugar cane on the next three Xs (One on left of _, skip _ over and fill two on right). Delete, and do the same for the next row. Do this until you reach the end.

I don't know if this will work. The middle rows of _s may fill up the middle areas you cleared. Im certainly going to try it...if it works, Im going to save myself A LOT of time.

Quote from Master_Buttchin

This method is very possible. The only issue is that the sugar cane's dirt block must have a side exposed ot water. Although its all underwater, the sugar cane acts as an airpocket, so the top of the dirt block its placed on is actually air. You need one of the sides of that dirt block exposed to water.

You can try making an alternating 2 block high pyramid of rows across the room underwater. Heres a rough text sketch, as though you're looking from the side:

X X X

_XXX _ XXX _ XXX_

. Xs are blocks of dirt. _s are blocks of water which will be directly contacting the outer Xs. You're leaving the _s to fill last, but may fill ones you've already passed as you make your way across the pyramids. Moving to the right, you would plant a sugar cane on the first two Xs on top. Delete them. Now add more sugar cane on the next three Xs (One on left of _, skip _ over and fill two on right). Delete, and do the same for the next row. Do this until you reach the end.

I don't know if this will work. The middle rows of _s may fill up the middle areas you cleared. Im certainly going to try it...if it works, Im going to save myself A LOT of time.

Can't place sugarcane under water, I tried.

Btw, yOu can just hold "LT". It acts like a turbo. No smashing required.

Quote from Puma_SPNKr

Can't place sugarcane under water, I tried.

Btw, yOu can just hold "LT". It acts like a turbo. No smashing required.

Quote from Puma_SPNKr

Can't place sugarcane under water, I tried.

Btw, yOu can just hold "LT". It acts like a turbo. No smashing required.

lol I know, im just so used to calling it mashing from playing total miner. Back to the sugarcane... I can plant it underwater, and this trick worked beautifully. You need a block of open space next to the sugarcane dirt block (regardless if you're above or underwater) filled with water for it to grow.

I just tried this trick, and the only improvement I would make is making the block below each pyramids "tip" hollow with water inside so that it may water the conjoining dirt blocks on the side (but keep in mind it wont water the dirt block above it).

EDIT: I had seen my X picture didn't come through very well. Think of a 2 block high pyramid with a block step on each side. That sugar cane needs water touching its dirt block, and you cant let the water run too close into itself. So, you have to position each row to have water touching it, while removing the water you've already passed through so it doesn't restore itself. This is why doing this is such a pain in the ass.

Once again, you can grow it underwater. You just need water touching the dirt block the sugarcane is on, hence making a hole next to it while underwater.

Quote from FayzedNZ

I think the best way to do underwater builds is to make your mold above water (provided the area on the bottom of the sea is flat) you put your base down 1 block above water using solid blocks (cobblestone,dirt etc) then make you mold with sand/gravel (filling it all in) now you just break your base out and your sand/gravel mold will fall to the bottom. You then just have to go and put your exterior walls (probably glass) around your mold. Dig you a hole inside close em up and have fun busting out your sand/gravel (using the torch method helps here for breaking them)

I like this idea very much, thanks! The only thing is that i wanted some water between my buildings roof and the surface. This idea sounds great for larger builds, but I can already see myself screwing up trying to coordinate how much sand lands in what spot to fill only so much of the area up. I would rather build my glass shell around my smaller builds and swim in to fill them up. Im definitely considering this for my bigger projects, though.