The Schnellebootewaffe And MAS Boats--General Discussion

Discussions on all (non-biographical) aspects of the Kriegsmarine except those dealing with the U-Boat forces.
varjag
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Post by varjag » 01 Sep 2006 03:56

Paul Lakowski wrote:I have a question. I was reading "S-Boote Geman Eboats in Action 1939-1945", and it was detailing the Sboote operations escorting troop ships to Norway in 1940. I gather the Sboote were used to ferry troops from the big ships to the shore and provide protection & escort. After these ports were secured , the Sboote operated for weeks later providing local coastal protection from the captured ports.


Reading these Sboote accounts , the operations normally radius was often 200-300km ,which was considered more than most smaller MTB operations. But the Norway operation was around 700km radius and the explaination is that a depotship or Fleet tender accompanied each Sboote flottila . So how was the Sboote range extended? Did the Tenders refuel the Sboote while they were steaming to Norway along with the troops ships? I know that Germans practiced replenishment at sea for the larger ships from Fleet oil tankers etc, but did these Fleet tenders also provide replensishment at sea for Sboote allowing them to exend operational radius of action?


Haven't read the book Paul - but did much 'ferrying' of troops take place in Norway? The laden troop-ships appear mostly to have moored at existing quay-facilities and debarked the troops and their equipment on the spot, judging by the picture material of that time.
The range even of pre-war S-Boote is given as of the order 600-700 miles (at 30 knots!?)
which was more than enough for them to reach southern Norway from Baltic/North Sea ports and quite a bit further at reduced speed. (I assume the data refers to 'land-miles' - not Nautical Miles) So - perhaps they only/mostly (?) did act as escorts. The German method of re-fuelling at sea was by streaming a hose behind the tanker - somewhat tricky for a small S-Boot....I venture to say that the crew 'doing their thing' on that small foredeck would have had a rather risky job.....my Tuppence, Varjag

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Post by Paul Lakowski » 01 Sep 2006 23:27

varjag wrote:
Haven't read the book Paul - but did much 'ferrying' of troops take place in Norway? The laden troop-ships appear mostly to have moored at existing quay-facilities and debarked the troops and their equipment on the spot, judging by the picture material of that time.
The range even of pre-war S-Boote is given as of the order 600-700 miles (at 30 knots!?)
which was more than enough for them to reach southern Norway from Baltic/North Sea ports and quite a bit further at reduced speed. (I assume the data refers to 'land-miles' - not Nautical Miles) So - perhaps they only/mostly (?) did act as escorts. The German method of re-fuelling at sea was by streaming a hose behind the tanker - somewhat tricky for a small S-Boot....I venture to say that the crew 'doing their thing' on that small foredeck would have had a rather risky job.....my Tuppence, Varjag


On the question of range, I speculated to myself that it would be unlikely that a ship would steam its entire range just to reach an enemy objective. That would leave the boat with no fuel when it could be in a position to need it the most. I suspect instead they would plan to have enough fuel to get back when they arrived, and then add some extra for combat fuel consumption....kind of like plane fuel plans. So the radius of action of a Sboote with 700miles @ 30knts would translate into a radius of action of say 250-300miles?

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Post by varjag » 02 Sep 2006 01:28

Agreed Paul - that under 'normal' circumstances - one doesn't run dry on ops.
But 'Weserübung' stretched the envelope. F/i - the destroyers arrived in Narvik with empty tanks, something similar may have pertained to the S-Boote? The entire operation was one where 'failure was not an option'. Once in Norway, the fiords and harbours would have provided sheltered waters for refuelling of small craft. Given the tight schedules - I still feel it unlikely that any refuelling of them was possible or allowed for - in transit to Norway. Besides the range for these craft (600-700 miles 'at 30 knots') - If correct, seems too long for me? - could have been much extended at the more economical speeds at which the transports were travelling. 30 knots is a very high speed and the transports probably did little better than 10 - 12, easing the thirst of the escorts.
Rgds, Varjag

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Karwats
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Post by Karwats » 02 Sep 2006 07:29

Gentlemen

I would guestimate the "economic speed" range probably around the 1100 mile mark, if not a bit more.Based on 600-700miles @ 30knots. Very difficult to say witnhout knowing the comsumption rates. But there is a HUGE difference between economical and max fuel rates on ships.

Stern RAS (Refeulling at Sea) is perfectly feasible, if uncomfortable at sea state 4 underway at 10 knots,we did it many times on our FAC (M). In this evolution the craft being refuelled is actually under tow and it takes around 1.5 -2 hours depending on your pump rates. So it is possible it was done underway, weather and swell conditions permitting- this type of operation does not get done with a beam swell running.

Range calculations for operations in my experience are always done at economical speed with a "balls to the wall factor" and reserve built in, both normally between 10-15% of total fuel onboard.Woe betide you if you arrive back in port under your safety margin- lots and lots of heel clicking on red carpets

:wink:

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David C. Clarke
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Post by David C. Clarke » 02 Sep 2006 07:42

Glad to see you back Karwats!!! :D

(By the way guys, I'm really, really proud of this Thread and ultra-intelligent posts in it! :D :D :D You guys have done magnificent work!! :D )

Very Best,
~D, the EviL

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Post by Paul Lakowski » 02 Sep 2006 20:57

varjag wrote:Agreed Paul - that under 'normal' circumstances - one doesn't run dry on ops.
But 'Weserübung' stretched the envelope. F/i - the destroyers arrived in Narvik with empty tanks, something similar may have pertained to the S-Boote? The entire operation was one where 'failure was not an option'. Once in Norway, the fiords and harbours would have provided sheltered waters for refuelling of small craft. Given the tight schedules - I still feel it unlikely that any refuelling of them was possible or allowed for - in transit to Norway. Besides the range for these craft (600-700 miles 'at 30 knots') - If correct, seems too long for me? - could have been much extended at the more economical speeds at which the transports were travelling. 30 knots is a very high speed and the transports probably did little better than 10 - 12, easing the thirst of the escorts.
Rgds, Varjag


I understand your point but nothing in the book suggest such a stretching of limits of range. remember the trip to Narvik was 2000km and I can see those escorts recieving replenishment from the tankers that were stationed their , for the return journey. But the general characterisation of the Sboot ops was 'no problem'.... to the extent that upon arrival at the ports the Sboot were immediately pressed into service transporting troops from the cruisers/depot ships ashore repeatly?

In the Schnellboote book , the S-7 was involved in the operations around Kristiansand and this is listed as having radius of 600miles and 'autonomy' of 800miles @ 20knts. The S-10 series increased this to 878miles and S-14 were able to reach 1000mile 'autonomy'.

I assume 'autonomy' = endurance?

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Post by varjag » 03 Sep 2006 05:13

Paul - looking at a map, Kristiansand that you mentioned - is about the closest point in Norway to the Wilhelmshaven/Cuxhafen ports on the North Sea - or about 325 miles.
Stavanger is about 400 miles away and Oslo - from a Baltic port, say Kiel - is the same distance, 400 mls. Given the ranges available to the S-Boote that we have established - they should have had little trouble getting there with some 'operational' reserve. A two-way trip without refuelling, is out of the question. Does your book say that an oiler of some sort accompanied each S-flotilla in the operation? Makes sense - if refuelling was envisaged, once they were in Norway. Despite Karwats experience with an FAC refuelling
at seastate 4 and ten knots - I question if the Germans were equipped for that in 1940.
Rgds, Varjag

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stril
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Post by stril » 03 Sep 2006 17:13

Hello
but did much 'ferrying' of troops take place in Norway?

If i have got things right it was the intention to use S-boats for ferrying of troops. In Kristiansand the S-boats was in front at the last attack into the harbour, with new orders telling them to go straight to the quay´s with the troops.
In Bergen 4 S-boats was used/intended for the attack, one damaged after a collision but eventally 3 was used.
All 3 was ferrying troops to diiferent locations in Bergen, not just quay`s. They was also damaged because of this use.
Quite a few pictures exist of these S-boats trip from Germany to Bergen along with Carl Peters, and their use in Bergen ferrying troops from the larger ships..
regards
stril

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Post by Paul Lakowski » 04 Sep 2006 01:37

varjag wrote:Paul - looking at a map, Kristiansand that you mentioned - is about the closest point in Norway to the Wilhelmshaven/Cuxhafen ports on the North Sea - or about 325 miles.
Stavanger is about 400 miles away and Oslo - from a Baltic port, say Kiel - is the same distance, 400 mls. Given the ranges available to the S-Boote that we have established - they should have had little trouble getting there with some 'operational' reserve. A two-way trip without refuelling, is out of the question. Does your book say that an oiler of some sort accompanied each S-flotilla in the operation? Makes sense - if refuelling was envisaged, once they were in Norway. Despite Karwats experience with an FAC refuelling
at seastate 4 and ten knots - I question if the Germans were equipped for that in 1940.
Rgds, Varjag



This was my original question, did the depot ships conduct refuelling at sea?

Here are some figures from
Group 3: 2500 troops ;193rd Infantry Regiment= Bergen & Stavanger: CL Koln, CL Konigsberg, 1 Auxiliaries, 1 Tanker, 3 Torpedo Boats [DE] , 1 Sboot tender & 5 Motor Torpedo Boats [Sboot]. (Two battalions air transported to Stavanger, the rest arrived by freighter.) 1 Tanker.

Group 4 : 1100 troops ;310th Infantry Regiment = Kristiansand: CL Karlsruhe, 3 Torpedo Boats[DE], 1 Auxiliary[Sboot tender] & 7 Motor Torpedo Boats[Sboot].

Note: There were 10 Freighters [360 troops & 500 tons]. dispersed between Groups 3 and 4 to transport troops and supplies.


The info in brackets is my summation.


On this site got the following info...[bable fish translation]
http://www.marine.de/01DB070000000001/C ... J082INFODE

· Group 3: Mountains
Light cruisers COLOGNE and KING MOUNTAIN
Artillery school ship BRAKE
Torpedo boats LEOPARD and WOLF
5 speedboats with consort ship KARL PETER
about 900 men landing forces
· Group 4: Kristiansand and Arendal
More easily cruiser KARLSRUHE
Torpedo boats LUCHS, SEIZE and SEA-EAGLES
7 speedboats with consort ship TSINGTAU
about 1400 men landing forces


So it does show one tanker in group 3, but no mention is made of refueling at sea...but no mention is made about refueling from the tankers. It says in the SBoote book pp 34


"However the presence of the Royual Navy creaed a real threat of which the Germans were well aware. The two S-Boote flotillas , stationed in the ports of Bergen and Kristiansand , were ordered to remain on location with their support ships."


I gather they were there until late April 1940. I guess they could have been visited by tankers in that time for refuelling or it could be done through the harbour?

I'm not sure about your point or refueling at sea? Germans were practicing this back in the Spanish Civil war.

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Post by varjag » 04 Sep 2006 12:31

This is really becoming exciting. Yes - I am aware of the German trials with - and use of -oiling at sea which are well documented. The tecnique of 'towing' with a hawser a n d a fuel-line likewise. Seems that the heavier ships and U-boats, had 'connector points' near the bow to flow the 'juice' into their tanks. Did the S-boote have something similar? And had they - received training in the rather tricky operation of refuelling at sea? In short - what I am in doubt about - is why a navy that sent 10 destroyers to an essential rendez-vous with a tanker in Narvik - would not have done the same with it's S-boote to southern Norway. In fact - I was a bit surprised to read that they also reached Bergen which is a lot further away than 'southern Norway - but confirms Karwats earlier post about their range which seems to become better with every post.....Varjag

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Post by Andreas » 04 Sep 2006 12:45

Bergen would not be much more than 550 miles (482 on the great circle, but that crosses land), so no need to refuel on sea.

All the best

Andreas

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Post by Paul Lakowski » 05 Sep 2006 01:58

Andreas wrote:Bergen would not be much more than 550 miles (482 on the great circle, but that crosses land), so no need to refuel on sea.

All the best

Andreas



I make the distance to Bergen > 500 miles so a return trip would require a range of well over 1000miles, when the 'autonomy' was listed at 800-900miles upto ~ 1000miles at most. That would not include any reserve and the additional fuel expended ferring troops from ship to shore, plus the additional fuel for staying on for a week or two to provide local security.

From this site I got...

http://www.german-navy.de/kriegsmarine/ ... story.html

Normally, each S-boat flotilla had its own S-boat tender, which was used to refuel and rearm the small fast attack craft and to serve as a floating barrack for the S-boat crews between their operations.


http://www.german-navy.de/kriegsmarine/ ... story.html

The Carl Peters class was build to support an equip the fast attack boats with torpedoes, depth charges, ammunition, fuel and fresh water, in addition they were used as floating barracks and hospitals for the small S-boats.

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Post by Andreas » 05 Sep 2006 09:00

No need to refuel at sea Paul. You can refuel at Bergen harbour.

None of the links provided thus far shows that S-Boote were refuelled at sea, or that they indeed had the technical capacity to do so. Karwats' experience is post-war, and many things had changed by then.

While submarines were refuelled at sea, they are considerably larger (Type VII has eight times the tonnage and is twice as long as the 1939 S-Boat), giving them much more stability.

Regardless, even if it was technically possible, I have serious doubts that it would have been undertaken during the march up to Norway. The risk of being caught while refuelling would have been very high.

All the best

Andreas

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stril
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Post by stril » 05 Sep 2006 09:40

Hello
The time used by the S-boats might tell something of the fuel consumption.
The main force(Group 3 heading for Bergen), Köln, Königsberg, and Bremse left Wilhelmshafen at 23:40. Around that time Carl Peters, Wolf and Leopard left Cuxhafen, and the S-boats left Helgoland.
It was the intention to gather the forces at position 56.20 N 06.20 E at 10.15, 8th of april but this was postponed because of fog The main force speed was 18 knots.
At 16.00 the fog was gone, and Carl Peters, Wolf and Leopard gathered with the main force. At 20:40 the S-boats was in contact with the main force(S-19, and S-21 collided a hour later, S-19 arrived at Bergen 10th of april), and 23:00 the force was 12 nautical miles west of Selbjørnsfjord, and at 23:40 they go eastwards into Korsfjord(Korsfjord aprox 60.08 N 05.00 E)
Added a part of a picture, S-boat alongside Köln in Bergen, early morning 9th of april 1940.
regards
stril

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Post by Andreas » 05 Sep 2006 09:46

Leaving from Helgoland knocks another 40-50 miles off the journey distance.

All the best

Andreas

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