Interesting New Released Drawings of the S class SSN Spartan

[Albacore 569]

Interesting New Released Drawings of the S class SSN Spartan Note the pump jest and the rudder stern planes, The are connected in these drawings dated 1967 and revised 1974

Are all our Trafalgar models with pump jets wrong then? Or was this an early evolution and modified later?

Source: https://archive.org/details/s106ga1974/page/n1/mode/2up

[Albacore 569]

Which stern is correct? Or are both but just at different times? The drawing says revisions 1974 period the left side shows Swifture's stern with propellor, and the right with the rest of the class? The drawings say they are for Spartan and Splendid. Expect the rest of the S class had the pump jet as the common cloud literature pushes. The rudder area for the both the pump jet and prop version appears same. Just the flow to the PJ intake has fixed rudder posts in drawing which avoids turbulent flow (noise) makes perfect sense. So are all models of the S class SSNs wrong and t class too? Or was this a early evolution of the pump jet shroud being incorporated. Photos of the astute on the ails before launching shows a separate shroud and planes arrangement.

[jphatton]

I think these general arrangement drawings reflect the design prior to construction, whereas the as built configuration may have been slightly different and during subsequent refits a range of modifications would have been made.

I did find this video from 2012 showing the decommissioned SSN's at Devonport including some Swiftsure class with pumpjets (see at 3:10 in the video, possibly these are right to left Spartan, Splendid, Superb and Sovereign based on some annotated aerial / satellite photos on the web ).

https://youtu.be/PnIQUMwsIvs?si=4TqJzpC9Tu7oNiGU&t=190

The rudder appears to be all moving rudder with only a short fixed portion just prior to the pumpjet, so at least by the end of their service life the configuration was different to the drawing.

[Albacore 569]

Thank you, JP. It looks like the video confirms the general arrangement drawings actually, that in service the S class were more different in modeling details. So, models of the S class are actually wrong, assuming the S boats were only shortened T boats, or more accurately, we assumed the T's were just lengthened S class. That was a wrong assumption, there are more variances between the two classes.

The squat upper rudder on the S boats always seemed a bit odd to me, why weren't they with the taller and separate upper rudders on the T class? Seems we are discovering the lower rudder had the same surface area, but squatter lower in profile.

Each class had one boat in each class with a standard if you can call an exotic submarine prop ever 'standard" Swiftsure the first in the S class, and Trafalgar in the T class. for base line comparison with the Pump jet boats performance tests.

See in the photograph, a fresh frame from the video you so helpfully provided. the PJ shroud is clearly attached to the back end of the fixed rudder stock, and if hard to see the rudder break line seems to follow the drawing too. That the Davenport photos show these faithful serving submarines after their service, seems that's the way they were always configured. Modelers seem to have gotten it wrong.

Evidence the T boats were the same? Photos I have of the T's reveal had separate control surfaces not attached to the PJ shroud

Steven

[jphatton]

Steven,

I went back through my files to see if I had any more useful photos available and found that there were a couple more photos showing the upper rudder and top of the pumpjet shroud. Here are links to the original sources:

In one of the UK government public consultation documents on the Submarine Dismantling Project from 2011 there is a detailed photo of the Swiftsure class upper rudder used to illustrate the introduction to Chapter 1 (see page 9). My assumption is that this photo is from Devonport Basin 3, showing the same submarines in the video.

https://data.parliament.uk/DepositedPapers/Files/DEP2011-1704/DEP2011-1704.pdf

This appears to show that the entire upper rudder is all moving except for a small stub just before the pumpjet shroud. Given that the Swiftsure class underwent a series of modifications during their service lives it is possible that they were built as per the general arrangement plan and the rudder arrangement was revised during a later refit.

There are various aerial photos online of the Devonport and Rosyth basins where the decommissioned British SSN and SSBN are stored. This is one of the best ones I've found of Devonport which shows various decommissioned Valiant, Swiftsure and Trafalgar boats

https://project-news.com/wp-content/uploads/2022/08/Submarnines-Number-3-Basin-Devonport.jpg

The second photo in this article provides an identification of the submarines in the Devonport basin 3 (looking in the opposite direction to the previous photo);

https://web.archive.org/web/20220207120518/https://www.navylookout.com/project-to-dismantle-ex-royal-navy-nuclear-submarines-inches-forward/

Direct link to photo

https://web.archive.org/web/20220207175424im_/https://www.navylookout.com/wp-content/uploads/2022/02/Decommissioned-nuclear-submarines-Devonport.jpg

Also Google Earth images can be useful for checking overall dimensions. One thing to consider is that at least for some submarines the rear planes have either been removed or clipped to allow boats to be docked closely together.

Jason

[Albacore 569]

Thank you sharing this forensic information. It is interesting the pump jets are already removed from Tireless and Turbulent. But the S boats the shrouds remain. We know Trafalgar in the same photo never employed a PJ, but I wonder why these were removed on the T's? You suggest for docking closer together.

It further confirms the T class PJ & stern planes are separate compared to the connect S class. Different. Besides docking space, I wonder if the PJ 's were removed on the T because they still have some security concerns or because removing same on the S boats is a much more elaborate process because they are attached to the stern planes? But if you look close on the S soats, the horizontal planes are already cut away for tighter docking.

It definitely shows are you been asserting the earlier drawings and the photos in Davenport show a rudder evolution between 1974 and their decommissioning (paying off). It has me thinking about a S class model of Spartan now reflecting the new information.