cann a bomb destroy a tank ?? when no direct hit?

[unreasonable]

Well it is about the difference between direct hits and near misses and why the latter are so much less effective than direct hits, so this is all OT. 

 

Panzerfaust was a shaped charge, as was the bazooka and the British PIAT.  But it is not the ideal AT weapon, that is still the high velocity AP of some variant. This is because HEAT is fairly easy to defeat with aprons or even junk hung around a tank, which makes the charge go off at a non-optimum distance from the armour and radically degrades penetration. (Modern reactive and composite Chobham armours also reduce HEAT efectiveness in a more high tech fashion). They also do not like being spun, so rifled barrels work less well. 

 

HEAT was and is the best choice for small infantry weapons or air delivered cluster type weapons, but the high velocity tank (or AT) gun firing a discarding sabot or similar round is still the most certain way to kill a heavy tank with a single shot.

[Gambit21]

...which exist for the specific purpose of causing spalling.

[unreasonable]

Assume you mean the high velocity shot, Gambit? I suppose that depends slightly on whether you think that the liquid plug of armour pushed in by a successful penetration is "spalling". I think of spalling as being solid flakes broken off the interior walls. This can happen after an AP hit, but it is not the intended method of destruction.

 

Kinetic shots exist for the specific purpose of penetrating armour, not creating spalling. (As do HEAT rounds).  AP and APCR are designed to penetrate and directly destroy crew, ammo, engine by transfer of kinetic energy. Any spalling from unsuccessful penetration is secondary and can be mitigated by interior linings. With well designed armour it may not happen at all.  If you get penetration you get transfer of kinetic energy from both the shot and the pushed in bits of armour, now mostly liquid, the ratio depending on the thickness of the armour. 

 

In contrast a round like HESH that causes massive spalling of solid flakes can destroy the interior of a tank without penetrating the armour at all.

 

HESH, HEAT and AP+ are totally different concepts of defeating armour.

[Scojo]

I wish Mythbusters were still running. We could collectively send this in. While most would feel it's not a "myth", it would still be fun to see them set off even more explosives

[Gambit21]

Unreasonable - thanks for that.

Perhaps I was misinformed a bit by reading "Death Traps" but from that I was left with the impression that (in WWII terms) a high velocity penetration results in spalling/solid shards of metal thus killing the crew. Further that thus was most commonly how the shot in question "killed" the tank. Not my area of expertise though.