if pakistan got OHP with 41MK VLS tubes, can we use them to launch babur cruise missile?

Unlikely...

For one Pakistan would likely use Babur on locally developed launching systems...i.e. a locally built ship using a locally built VLS. Hence having naval LACM capability will take a fair while as the systems involved are pretty daunting. I don't even think the Navy will use Babur, but rather a different missile...guess a logical course of action would be to synchronize local VLS development with possible MR-SAM and LACM development.

Secondly, the Mk.41 on OHP would exclusively be used for ESSM and possibly VLA-ASROC.

Diameter wise, the Barbur cruise missile won't fit.

check out the engineering dynamics of this system... a lot of fluid mechanics and thermodynamics invovlved. (mechanical engineering)

http://www.fas.org/man/dod-101/sys/ship/we...41-tactical.pdf

There are three key questions involved:
1. Would the diameter of Babur be sufficiently small to potentially fit a Mk41 VLS?
2. Would a strike length Mk41 VLS fit the OHP?
3. Would it be (cost-)effective to fit OHP with 8, max. 16 Baburs, as compared to e.g. ESSM, ASROC.?

The answer to one is: possibly (there are some sources which claim it is very similar to Tomahawk)

The answer to two is: depends. (The Australian refit of the OHP features a MK41 tactical module which is short and does not fit much that is longer than ESSM (about 4-5m) while Babur is said to be 6-7m (depending on whether booster stage is counted). But this refit put the Mk41 unit well forward of the Mk13 single rail launcher, into the bow area where there is little depth. If we were talking about an ex-USN OHP which had the Mk13 removed then MK41 units could be placed there instead, and at that point in the hull there might be enough depth to put in strike length Mk41 VLS. However, I would suspect the number of such units you could put in would be limited to 2, perhaps 3. It would be a far more substantial structural operation than the Australian refit (which is already somewhat pushing it in terms of extra weight the IHP can handle).

The answer to three is: probably not. Assuming Babur can fit Mk41 and strike length modules could be fitted to the OHP, you're looking at max 16 land-attack Babur in 2 long modules plus 32 ESSM in a single short module, with the ship not having any SSMs (e.g. Harpoon). It would be major surgery on the ship and would push the limits of weight she can handle. This mean expensive refit, for a limited and not so stealthy delivery platform (compared to a sub-lauched version)

If OHP comes to PN, and they are without Mk13/SM1, I would be for a small refit, giving the ships 32 ESSM in a single tactical Mk41 (8 cells) and 2x4 Harpoon (deck lauchers where the Mk13 use to be) and a senser/command system upgrade. Not more, not less (well, maybe just a 21 round RAM launcher in place of the Phalanx CIWS).Wouldn't bother with ASROC, given 2 shipborn helicopters.