Battle for the Phillipines: 1944

[Kitsune]

Was asking others to look up some more information, I was told:

According to "Ship's Data: IJN Warships 1868-1945, Vol 1 Battleships and Battlecruisers" (a new J 'BB bible' according to some) the original design speed was 26.5kts at 80k shp, Nagato's trial result was 26.443 at ~85.5kshp and 'planned' displacement of 37,396, Mutsu's 26.728 at ~87.5k shp actual displacement 37,076 tonne. After modernization the design speed fell to 25 knots, trial results 25.8 at ~88.4k shp, 43,581 tonne and 25.28 at 82.6k shp, 43,439 tonne, respectively. The nominal design power was the same, though boiler outfit changed and steam conditions changed slightly too. Std/Full load displacement was 32.7/39-40k k tonne before and around 39.1-39.4/45.8 k after modernization.

[Sea Skimmer]

Well if someone’s got actual trial results, then I’ll accept those over combindfleet. As I far as I can tell (had to guess at the added distance from zigzagging, I used 20%) a Nagato would have burned significantly less then 1/3rd its fuel load by the time it reached the battle zone, so none of this ever mattered anyway.

Going back to fouling though, I found an interesting bulb in the book War Plan Orange when I was skimming it for unrelated reasons, page 279, the USN expected that the battleline to be reduced to as little as 15 knots during a Pacific campaign from fouling! That’s a lot worse then I ever expected. Another bit said more specifically that one day out of dock in tropical waters was thought to equate to a loss of 1/10th of an RPM for a propeller. That’s direct loss of revolutions, something I wasn’t considering, not just increased drag on the power the ship does have.

So I did more digging to confirm/deny this and found a very nice report on the matter
https://darchive.mblwhoilibrary.org/bit ... er%202.pdf

To summarize its main points, bottom fouling can increase resistance by as much as a third of a percent per day (and this was in Japanese home waters, not as bad as the real tropics) and a year out of dock will outright double hull resistance. So no doubt about it, the American fleet was going to be slow down a lot between the long periods out of yard, and overloading so excessive as to force the removal of turret armor. The IJN will suffer too, but it can't help but be by less.

[Kitsune]

I did a reasonable scan of the article, avoiding the formulas of the page.
I did note something that you did not stress. That is the discussion of new special paints.
Most of the research of the article was done in the thirties and War Plan Orange is in the Nineteen Twenties, later discarded for an island hopping campaign.

Near the end of the part of the article about coatings, they discuss that in World War II that the extra consumption of fuel of 3% per month out of dock was not realized and stating that they are not sure if that was due to wartime tempo or due to better coatings. They still make it certain that the new coating do make a difference in general performance and the importance to maintain them.

I don't know if you served in a Navy or not but I did serve in the US Navy. It has been many years ago but I dimly think remember having divers over the side to clean the hull. I don't know where sources for such actions in World War II would even be found but I think a reasonable assumption would be that it was done. They did anchor out of combat areas and they did not have the safety precautions which the United States Military operates with today.

I guess that paints even more improved during the time between the article was written and when I served in the 1980s because we were in dry dock only once while I on board around 3 years while we could still reach our expected top speed. We may have even been only pulled from the water because we had a side collision with a destroyer which buckled some hull plates (They did not leak but were bent) during a training operation (I was on an Amphibious Cargo Ship but we were practicing refueling the destroyer when the destroyer lost steering)

As well, where I work at during nights, the USS Truckee is being scrapped and there is no real fouling on the exposed portion of the hull (They have removed much of the superstructure and some of the hull and her waterline is exposed) She is a World War II Hull.

I am not trying to argue that fouling is not a factor but that it is likely a lesser factor during World War II, even when the vessels went protracted times out of dock, than you seem to be suggesting.

[Kitsune]

Since there appears to be no real argument back on the fouling issue, I will go on to the next subject we were discussing. That is the issue of destroyer weights.

First off, in few of the discussions have people expected me to provide page numbers. I usually only provide if asked. Second, you state that you have had Friedman's US Destroyers for years. The versions I was using was Google Book's which is the updated edition so odds are that the page numbers would not match anyway (I finally found a fairly cheap copy on Amazon Marketplace - While listed under the new edition, it could very well be the old edition. Still for $25 and I will now have his Battleships, Carriers, Cruisers, and Destroyers)

Yes, I was using the Benham class but even at heavier displacement, it reached 37.9 knots at 2,038 tons. Other class also exceeded their designed speed. Dunlop class, Gleave class did 36.5 knots at 2,220 tons when she was designed for 35 knots at 1,817 standard displacement.