Portholes in warships

[Mikel2]

I was looking at this photo of Prinz Eugen in Boston, in 1946, and I was wondering what the rational was for having portholes in heavily armored ships.   I assume the compartments with the portholes are outside the armor belts, so those don't make much of a difference armor-wise.  Are these big enough to allow evacuation from the ship if needed?   I assume modern ventilation and NBC systems made portholes unnecessary or a liability.

 

 

I notice the Iowas don't have any.

 

[beans4]

Not that I'm a naval expert, but thanks to Drachinifel I know that the Iowa class has their armor separate and internal from the outer hull, so portholes not feasible.  Presumably they had some other means of ventilation.  But yeah, seems like a lot of pre WWII ships did have portholes.

[sunday]

21 minutes ago, beans4 said:

Not that I'm a naval expert, but thanks to Drachinifel I know that the Iowa class has their armor separate and internal from the outer hull, so portholes not feasible.  Presumably they had some other means of ventilation.  But yeah, seems like a lot of pre WWII ships did have portholes.

But they also used the all-or-nothing design principle, so the forward and aft parts of the hull, before A turret and after C turret, were unarmored. Well, kind of, as the Iowas used a lesser grade of armor steel as structural steel in these parts.

I guess better ventilation/air conditioning was one of the main reasons to not put portholes.

[RETAC21]

6 minutes ago, sunday said:

I guess better ventilation/air conditioning was one of the main reasons to not put portholes.

This. Portholes were a clue of weakened armor, but they were needed to get air inside the ship, but as air conditioning systems became more common they went away. See Maryland BB-46

1920:

http://navsource.org/archives/01/046/014633d.jpg

1945:

http://www.navsource.org/archives/01/014662.jpg

[Inhapi]

The Portholes were only in unarmoured parts of the ships. No one put a porthole into an armour plate. (not counting hatches in decks and bulkheads ofc)

In/after WWII they wre also eliminated from unprotected parts of the hull, made possible by better mechanical ventilation to imorve the watertightness of the hulls. This was also ofc jsut due to the fact that in wartime a lower standard of crew comfort was acceptable for bettr combat effectiveness.
 

[Inhapi]

7 hours ago, RETAC21 said:

This. Portholes were a clue of weakened armor,

No, they were never put in armoured sides of ships.

IN fact looking at a BB and seeing where the portholes are, you get a good picture of where her side armour be it thick or thin is. Parts with portholes are unprotected.

Edited January 25, 2023 by Inhapi

[Inhapi]

8 hours ago, sunday said:

 

I guess better ventilation/air conditioning was one of the main reasons to not put portholes.

This allowed to get rid of portholes and make the hull better watertichgt in damaged condition. A porthole, even in a totally unarmoured part of the ship,; still poses a flooding risk if the ship settles deeper in the water after some hits. This is much like the situation where you want a few holes as possible in watertight bulkheads.

[shep854]

Drach has pointed out how certain British treaty cruisers happened to lack portholes in portions of their hulls, which conveniently allowed armor to be installed when needed.

[RETAC21]

16 hours ago, Inhapi said:

No, they were never put in armoured sides of ships.

IN fact looking at a BB and seeing where the portholes are, you get a good picture of where her side armour be it thick or thin is. Parts with portholes are unprotected.

Yes, of course, this is what I meant, but not what I converyed.

[Mikel2]

When did warships begin to equip chemical protection? I assume by WWI this was a credible threat.

[Mikel2]

4 hours ago, shep854 said:

Drach has pointed out how certain British treaty cruisers happened to lack portholes in portions of their hulls, which conveniently allowed armor to be installed when needed.

I can see dummy portholes installed to fool unfriendly observers 🙂

[Ivanhoe]

On 1/23/2023 at 7:25 PM, Mikel2 said:

I was looking at this photo of Prinz Eugen in Boston, in 1946, and I was wondering what the rational was for having portholes in heavily armored ships.   I assume the compartments with the portholes are outside the armor belts, so those don't make much of a difference armor-wise.  Are these big enough to allow evacuation from the ship if needed?   I assume modern ventilation and NBC systems made portholes unnecessary or a liability.

So they could run oars out and use "ash wind" if the engines failed.

I notice the Iowas don't have any.

Better engines.

😉

[Rick]

Lighting, ventilation, and tradition. 

[rmgill]

On 1/25/2023 at 1:26 PM, Mikel2 said:

When did warships begin to equip chemical protection? I assume by WWI this was a credible threat.

Were chemical weapons ever envisioned for naval use? I'd expect that crews having access to Gas masks would be sufficient as the ship can move out of the cloud like it could in and out of a smoke screen. 

[kokovi]

3 hours ago, rmgill said:

Were chemical weapons ever envisioned for naval use? I'd expect that crews having access to Gas masks would be sufficient as the ship can move out of the cloud like it could in and out of a smoke screen. 

At least German navy vessels have sprinkler systems on deck to wash away both fallout and chemical weapons. The idea is to form something like a water umbrella to protect the ship against such stuff. 

[sunday]

Here is a mostly theoretical article on gas warfare and USN ship personnel published in 1931

https://www.usni.org/magazines/proceedings/1931/may/ship-personnel-and-gas-warfare