Boat inflicts fall damage if it runs aground in some fashion (Slabs, Mobs, Soul Sand)

I have not tested it in 1.4.5, but if it hasn't been explicitly fixed, I suspect it's still there. Brian: Rather than giving up boats, I started leaving the cats behind. (It's easy enough to avoid squid.)

Tried some testing in my playground world... I wrecked several boats without damage, then took a heart and a half of "mystery damage" when running over a cat <i>without</i> wrecking the boat. Comparing with the bugs marked as duplicates, it looks to me like the "fall distance" from bobbing accumulates very slowly, and it's not clear exactly what triggers the "impact",

Also, a decent workaround is simply to get out of the boat and take a swim every so often, especially before approaching land or mobs in the water.

It's still there in 1.4.6.
And I wouldn't say that the fall distance accumulates very slowly. Just going far enough away from a cat to make it teleport to you is long enough to accumulate a fatal amount, so if a cat teleports underneath your boat, you will die for sure.

Still there in 13w04a. I clipped a squid, and died with the 'hit the ground too fast' message. But on other occasions I've hit a squid and just had the boat break. Which is also annoying, and also, I feel, a bug, but fatal falling damage when boating is definitely an intermittent problem.
I haven't enountered this particular bug in a while, so it's probably an edge case. Could it be related to the issue where hitting lilypads sometimes breaks the boat and sometimes not? Could the vulnerability be hitting the boat's front corners at just the wrong angle?

Summarizing the "boats inflicts suffocation damage" to one issue.

I just experienced this in Minecraft 1.4.7 . My boat was in flowing water block, being pushed into grass blocks (I thought this would be a good way to dock the boat). I got in the boat and attempted to push off by pressing "w" key. Nothing happened initially, so I continued holding down the movement keys for a few moments. Without warning, I got the "Hit the ground to hard" message on the death screen. I have not been able to reproduce.

Spot fix
I modified the fall state calculations "just enough" to handle this boat case, but it might be better to also allow this for all entities, as I don't see any significant bad reasons to reduce fall distance when going back upwards, no matter what entity and for what reason.

(MCP naming etc.)

Entity

protected void updateFallState(double verticalMovement, boolean onGround) {
    ...
        } else if (verticalMovement < 0.0D) {
            this.fallDistance = (float) ((double) this.fallDistance - verticalMovement);
        } // FIX:
        else {
            if (this.fallDistance != 0 && this instanceof EntityBoat) {
                this.fallDistance = (float) ((double) this.fallDistance - verticalMovement);
                // Reducing it a bit over time to handle floating-point error accumulation.
                if (Math.abs(this.fallDistance) < 0.1D)
                    this.fallDistance = 0;
                else
                    this.fallDistance -= Math.signum(this.fallDistance) * 0.1;
            }
        }
    ...
}

Tested the changes on 1.4.7 and at least the normal boating accumulation was corrected to 0 (with minor random fluctuations, from the bobbing). Also, long distance falls (e.g. from waterfall) were still handled correctly (i.e. accumulated plenty of fall distance).

Background info
While testing this, it became apparent that the player itself does not accumulate fall damage (at all) while going around in the boat, but the boat does so, slowly, and it does have some weird effect into it, too (showing two different values, one a scaled version of the other). I had to stay in the boat for couple minutes to gain fall distance of about 18 blocks (effectively 15 blocks when calculating damage).

The boat will transfer the "fall" event to riding entity (player) when applicable. After reaching boat fall distance accumulation of about 24, I rode it into the slab platform and it resulted in, actually, two separate "falls", one for 18 blocks fall distance damage, the other for 22 blocks fall distance damage. (Not sure if both caused damage, but at least both fall events were acted on by the boat and delivered to the player entity, and had about half-a-heart health left after the "accident".)

Affects 13w09b.

Reproduction hint: first creative mode, create slab-platform (so that there is half-block drop down from water surface to the slab surface), get some boats into inventory, switch to survival mode, drop boat to water, idle in a boat bobbing on the waters for 3-4 minutes, move with the boat onto the platform. Hurt-a-plenty.

This bug has been in the game for a long time and I'd really like to see it fixed soon. As it is there is no safe way to land a boat at high speed. Running the boat aground (say onto soul sand) is a way to land without breaking it, but thanks to this bug it kills the player. Fixing this bug would make boats much more viable for transportation.

The speed at which one eventually brings the boat to land doesn't affect this issue (although it is still not advisable to land at high speeds due to the other correctly working mechanisms). One can pretty much "sneak" in as carefully as possible, and still it hurts just as much.

The workaround I use currently, although the reason is the stupid way the game randomly places the character once out of boat, is to leave the boat a little before touching ground and swim the rest of the way.

Markku, I assume you're referring to my comment when you say speed doesn't effect it and you're correct with regard to the fall damage bug, but a related fact you're forgetting is that running aground (which causes the fall damage) is a way to land a boat at high speed without breaking it. You can crash a boat into soul sand at full speed without breaking the boat, but you often take damage because of this bug. It would make sense if the damage was based on your speed, but it's based on how long you've been in the water. I don't even think it's based on an accumulation of vertical movement, because when I ran a test trying to accumulate a bunch of vertical movement from moving up and down a water flow I didn't take much extra damage. There's just some bug that causes fall damage to accumulate while you're floating at sea and release when you beach the boat.

No need to make guess work about whether it accumulates vertical movement or not. My earlier comment (with the fix) explains it quite a bit.

All entities (except those specifically overriding the behavior) accumulate vertical movement because only the downward movement is summed, and the upwards movement is ignored. Normally when entities move down, they are either flying (which explicitly handles things properly) or falling. When falling, the movement is naturally only downwards (until hitting something solid or liquid) and thus ignoring the upwards movement is ok.

But, when in a boat, the boat moves both up and down (its bobbing on the "waves"). Since it is not on solid ground, it is considered to be falling. The fall distance accumulates from the downward movements. It takes quite a while, minutes for a large enough distance to cause good amount of damage.

Note that following parts of the code are needed for handling normal falling (and its damage): boat thinks its falling when its on water surface; recording the distance traveled down; transferring the distance from boat to the rider (player).

In short, the only thing that isn't working as one would expect is the ignorance of moving (back) up and how it affects fall distance. And that is what my fix corrects.

Edit: reread my earlier comment, and I did write about accumulating fall damage. Ooops. It accumulates fall distance, which is separately converted to damage when things hit ground.

I was just killed in 1.5.1 by a cat teleporting beside me or under me, so this bug is still around in the latest version.

Same here, 13w18c: I was traveling by boat trying to bring a newly tamed cat back to my home, when suddenly I died because "player hit the ground too hard". Fortunately I was already close enough to home so that I was able to salvage all my equipment. (The cat seems to have died in the accident though.)

My first death on my new survival world was caused by a boat. Lesson: Never ever build docks again.

Confirmed in 1.5.2 – a cat again. Ran back bare-naked to get my stuff, and actually got it....

Markku - 07/Mar/13 12:21 AM wrote that you need several minutes' worth bobbing up and down. But to me it happens in less than half a minute. I built a dock somewhat similar to the many examples. The boat hits a half slab, and boom; Hit the ground too hard!

Luckily our hardcore server wasn't really hardcore and I could get back in.

I can confirm this in 1.5.2 as well. I had a rather nasty and unexpected encounter with the bug when I just lazily coasted into the dock I built in the LAN world I play in alongside my brother. I used soul sand as bumpers so the boats wouldn't explode when either of us careened into the dock (having forgotten about this bug with it, bit of a derp on my part), and when I just gently floated into the soul sand, the moment I got out I was INSTANTLY killed. My brother was also instantly killed by this bug when he made contact with soul sand and got out of his boat, but I don't quite remember if he coasted into the sand or not. The fact I instantly died, though, just from gently floating into the soul sand from a distance that amounted to two steps away kinda shows how bad this bug is.

ArmEagle, note that the couple minutes of bobbing I mentioned was needed to accumulate about 18 blocks worth of fall distance; less time means less accumulated distance, but IIRC, more than 3 blocks is enough to cause damage.

There could be other methods than the minutes of bobbing I used for gaining the fall damage, or code may have been changed after I made that testing/debugging. In any case, that bobbing on the waves was the only way I managed to reproduce the issue. If someone can provide step-by-step instructions for another method that at least somewhat often results in the issue, I can debug and perhaps fix that case, too.

Also, the value of the accumulated distance varied rapidly quite a bit, so with short enough time, the value could vary between more than 3 and less than 3, basically making it a bit of random whether landing at that time causes no or just a little damage. That is, testing this with only short period on water is unreliable (or triggers some other bug/mechanism); to test properly, one has to stay on the water long enough to ensure that fall distance will be large enough to always hurt.

I just had an issue with this bug on my HARDCORE world. I died.

I was riding in a boat and I had about 4 cats that I had bred. I was moving from one location to another and the cats teleport to you as you move. Well one of them hit me in the boat and the boat broke and I instantly died from 'falling' according to the death message on screen.

Luckily I had only about 5 or 6 hours invested into the world thus far...

I am on Minecraft Pre-Release version 1.6.2

This bug has been in Minecraft since about BETA 1.6 or 1.7, I think, and was reported way back then. And it's deadly with only a few seconds of riding in a boat. I'm not sure how long exactly, but it's definitely less than 10 seconds. I think this bug is a side effect of very crude, lazy fix for a bug that made you immune to fall damage while in a boat. That bug was exploitable, but was almost never exploited because it was so useless. I've never been in a situation where exploiting the fall damage immunity bug with a boat would have worked better than just going down a temporary waterfall.

This could be fixed by just bringing back the old fall damage immunity bug, but apparently Notch decided that it was more important to fix a very rarely (or maybe never) useful exploit than to fix an instant-kill bug that can only be completely avoided by NEVER using boats. You see, it happens with squid too, and those things are everywhere.

And this isn't the only bug that instantly kills you. Hardcore is unplayable with all the instant death bugs that Minecraft has.

As I have commented earlier, if anyone (perhaps "A Full Name" (woodensword)?) knows of a reproducible method (step by step, please) to cause the issue as quickly as advertised (less than 10 seconds), or any other method than the long one I found and used, please tell about it, so that it can be tested and debugged.

The fix I provided is only for the method I was able to find and do repeatedly for debugging and checking that the fix works. Also, things may have changed since I did the previous testing, its soon half a year and couple major versions old stuff (and getting in danger of becoming something that can not be applied directly; oh well, Mojang's own fault if they do not bother to fix things quickly in reasonable time).

And bringing back another bug is not a "fix"; it is, at best a compromise, at worst a bad workaround. This issue seems to be something that can actually be solved and properly fixed. Well, as long as Mojang wakes up. But if they do wake up, they can just as well fix this properly, instead of just juggling with different bugs.

If you ride in a boat and get a few dogs or cats to follow you you will die like I said above. Because they teleport to you and the death message will say ******* fell from a high place.... I have reproduced this several times within a few seconds...

I was unable to get 3 dogs to teleport to me in the boat, though they teleported to nearby land (or behind the movement judging from the splash sounds) once close enough to land. And to get far enough, it took certainly more than "few seconds" for even the first trip (tens of seconds would be more appropriate estimate). (In the end, I made 300+ blocks trip to see if I could force them to teleport by so large separation that they would get unloaded; they failed to teleport at all.)

Anyway, the dogs/boat failed to cause any damage. Not quite the step-by-step repeatable instructions I am seeking for.

What's the point of fall distance, anyway? Why not use actual energy (proportional to velocity squared) at the time of impact? That would kill all the bugs like this one that have popped up over time. Is that behavior not what players expect? The only 'good' thing about fall distance seems to be that knockback into the ground won't hurt, although the value of that is debatable.

Fall distance is a good way to calculate impact energy, assuming your trajectory is a perfect parabola segment with well-defined endpoints. It shows.

I was about to build a dock before I (fortunately) saw this thread. Sounds like a stupid bug. Vote +1.

Confirmed for 1.6.2.

Can a moderator or OP please update the Effected Versions?

I just experienced this bug in 1.6.2. I was pulling a cow by a lead while in a boat and had to turn around. After colliding with the cow, I died instantly, being at full health and armor, with the message saying I "fell from a high place."

annoying bug, still happen in 13w37b

Still a bug in 14w8a

This just happened to me in 14w11b. I was riding a boat into Soul Sand when I died with the "fell from a high place" message.

Confirmed in 1.7.10. This is especially troublesome when you attempt to "beach" a boat onto Soul Sand or Half Slabs to avoid it shooting off as reported in MC-42027.

Confirmed for 14w29b, just happened for the first time while trying to dock on half slabs. Very frustrating that the boats are nearly impossible to exit in any way without either destroying the boat, shooting it off into the ocean or dying instantly! This issue seems to have been around for a long, long time.

Squid killed me while in my boat in 1.8-pre3.

It seems to me that this has gotten a lot worse in version 1.8. It never occurred to me in 1.7.10, where I sailed a lot. It has now occurred trice for me i 1.8 over just a few days of play.

Also, as far as I can see, I am not doing anything differently than I used to, while in the boat.

The last time it happened, I entered the boat on shallow water (1 deep) and was killed almost instantaneously (within a second).

No soul sand or half slabs were involved in my cases.

Could not reproduce in 1.8 SSP. First I circumnavigated a continent and docked on slabs without damage, then I tried idling in a boat for 4 minutes before docking on slabs (as suggested by one of the comments here) and again took no damage.

Playing multi player: While approaching land at low speed, I died from falling. Don't think my boat hit anything. Not sure if another player's boat hit my boat. But strange to die from falling while in a boat in water.

Sharon, "But strange to die from falling while in a boat in water."

If you read my old comment (more than 1.5 years ago) on this issue, you'll see "why" it is reported as fall damage. Just a bug in the code that tries to track the fall distance (i.e. damage) of the boat. The incorrectly calculated fall distance/damage then manifests in many seemingly unrelated situations (which in turn is the effect of overly simplified and badly designed physics rules).

However, there may also be other causes than the one I found and provided a fix for.

Ok this sounds like exactly what happened to me, sailing in 2 block deep water, 5 blocks offshore,
guess the bobbing ? was the points when it blinked showing water in the boat while crossing the ocean.
I slowed to look at something onshore , heard a sploosh and died instantly.
There were no squid or other mobs around, but I was drifting close to a 1 block deep area of water.
One month later and I still have not found the exact spot where I died, trying to find all my lost goodies and a written book.
After dying 2 more times during my searching for lost items, I have taken to just swimming across the ocean rather than trying to use a boat !
And YES this is still present in 1.8.1 !

@ /u/Anomie X , sail longer distances more often, it's sporadic but IT Happens !

I think I know what's going on here and how it can be fixed.

Fall damage is dealt in the following manner: If an entity is not OnGround (their feet aren't touching the collision box of a block) and they have a downward velocity, FallDistance counts the distance they have fallen. The next time the entity is OnGround, fall damage is applied depending on the value of FallDistance (and FallDistance is reset).

FallDistance is reset in certain cases, such as landing in water, mounting/dismounting an entity, or sleeping.

When boats move slowly, they bob up and down. When riding a boat through water, the player is not OnGround, so they slowly accumulate fall damage. Ordinarily, this is reset upon dismounting, but running aground on certain blocks or running into mobs causes the damage to be dealt (if there is enough FallDistance accumulated to hurt the player). Whatever caused this odd behavior used to occur all the time, but the "fix" in 13w39a made it rarer.

This does not happen when a player is swimming because the fall damage is constantly being reset because the player is "landing" in water. Apparently, falling while riding a boat does not count as landing in water.

The Fix: Reset FallDistance when an entity gets an upward velocity.

If this was so, the player's FallDistance would reset when the boat bobs back up. So, there would never be enough FallDistance to hurt the player.

This fix would not affect the normal dealing of fall damage. In fact, this a much more realistic mechanic, as all downward momentum gets cancelled out when an object is forced upward.

This would also fix a similar problem with mobs strung up on leads: Mobs bounce up and down when hung from leads, so they often accumulate enough FallDistance to kill them as soon as the lead is broken. With this fix, they would take fall damage only from the fall of being released from the lead.

This bug is still present in 1.8.1, by the way. I tested it.

Yes , still present in 1.8.1
It is also a bit aggravating that the boat shoots off out across the water when you exit the boat several times while sailing,
just to get rid of this collected fall damage. Sometimes it shoots to shore where it crashes and is destroyed.
Swimming the ocean is much safer than trying to sail ! ! ! At least then when I drown it is because I took my thumb off the spacebar !

Boats don't shoot off if you face west when dismounting. Just do that until it gets fixed.

Thanks for the "West" clue, but I think I will stick to just swimming an do away with any boats,
untill the sudden death syndrome is fixed !

BoxFigs, if you didn't yet, you could take a look at my earlier comment 21/Feb/13 5:12 PM... Of course, it has been so long it isn't necessarily completely valid "as is" any more.

@unknown & @unknown: I think the fall distance mechanic should be changed radically. Ideally it'd be abandoned in favor of velocity squared, but that's probably too radical. It's too ingrained and some people rely on the current mechanic. Minecraft could instead save the apex. It's essentially fall damage in a different form, the benefit being that it's less prone to integration mistakes. It's also numerically stable, although I don't believe such instability is significant.

@jonathan2520

You mean it would be based on where your feet stopped touching the ground?

This is still a concern in Minecraft 1.8.3. I was playing hardcore, too 😞

I came across some code that would explain why I couldn't reproduce this earlier but other people still report the problem.

It appears they attempted to fix this sometime between 1.6.4 and 1.7.2 by having boats not accumulate fall distance when they're above a water block. But the test is slightly bugged: the boat isn't actually on top of the surface water block, it's slightly inside of it (the boat's Y is about 3.9 on a water block at Y=3, rather than 4.0 like standing on solid ground), so the block "below" is actually the block under the surface water block (at Y=2). When I tested I was in deep water the whole time so no fall distance accumulated, but whenever you're in shallow water (e.g. a swamp) the block underneath is not water so the fall distance will accumulate as the boat bobs. And deep water doesn't reset fall distance, it just doesn't make it worse.

Further, the normal "reset fall damage when in water" doesn't usually apply to boats because that only occurs when the entity is farther into the water block than boats normally get. It looks like it would have to get down to about Y=3.599 in that water block at Y=3 for that to happen.

I was just instakilled by what I assume was this bug. I was travelling along a river; gently bumped a squid and died instantly.

Still happens with 1.8.4. I just encountered this bug today after driving my boat to a dock and getting out of it. The dock consists of a wood slab in between 2 wood planks. The slab is at water level to allow the boat to sit on top and get out of the water. I was able to dock the boat on top of the slab, but I died as soon as I left the boat.

I can confirm this still happens in 1.8.8. I was very upset after just collecting my items from the bottom of the ocean to pull into my boat dock and get killed the second the boat hit the slabs it rests on to "park". However I was in deep water most of the time, so not sure why this happened.

==========================================

OK I did a test. I can confirm Anomie X's explanation to this issue. I went into shallow water (1 block of water) and bobbed up and down for a few minutes, then tried to "dock" on some slabs and almost got killed. I repeated this test in deep water and no damage at all.

I did it in 15w32c, I bobbed for a minute or two, and took 3 hearts of damage. Oh dear.
However, when i did it, the boat broke too.
The first time i did it, the boat broke and i took no damage(with feather falling IV).
the third time, I let it bob, went to eat breakfast, and discovered me hitting the ground too hard.

This happened to me in 1.8.8 I made a dock with soulsand because I had heard it stopped the boat from breaking, this was not the case... The boat broke and (at the same time?) I died due to "fall damage".