Fouled hulls causing loss of speed

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Andy H
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Fouled hulls causing loss of speed

#1

Post by Andy H » 06 Apr 2004, 23:57

One of the major problems facing the RN during both WW1 & WW2, was the fouling of ships hulls which caused a reduction in speed, which given the state of warfare at sea at the time could prove crucial in staying afloat.

Does anyone know the typical speed reduction for a ship with a fouled hull?

Andy H

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#2

Post by Xavier » 07 Apr 2004, 00:20

not loss of speed, but more fuel consumption (in the end, it is the same thing...) I think the data applies to all ships.
from: http://www.cda.org.uk/megab2/corr_rs/tn30/sec15.htm
Close monitoring of the operation of these vessels has shown that the steel hulled boats need to be taken out of the water for cleaning every six months whilst fouling of the copper-nickel hull is minimal. Initial fuel savings were about 15%. This figure grew to nearly 50% when compared with a fouled steel hulled boat due for cleaning. After four years the steel hulls were so far corroded as to need significant replacement of plating
more data in the link


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Xavier
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#3

Post by Andy H » 10 Apr 2004, 02:04

Sorry Xavier I thought I had posted a response to this days ago.

Well a belated thank

Regards

Andy H

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Re: Fouled hulls causing loss of speed

#4

Post by varjag » 12 Apr 2004, 13:21

Andy H wrote:One of the major problems facing the RN during both WW1 & WW2, was the fouling of ships hulls which caused a reduction in speed, which given the state of warfare at sea at the time could prove crucial in staying afloat.

Does anyone know the typical speed reduction for a ship with a fouled hull?

Andy H
Depends of course on how bad (old) the fouling is and Xaviers note of increased fuel consumption is noted. When the SCHEER was about to break-back to Germany her max. speed, due to fouling, was down to about 24½ knots. In a de-fouling operation undertaken in the South Atlantic (the ship was ballasted to a 15-degree or so list, alternatively port and starboard - and before bunkering for the return - so she was relatively high in the water) she regained a top-speed of about 26 knots but managed in tight corners and with everything taken out of the diesels, almost 27,3 knots. I may be wrong - but understand that the fouling is most severe on waterline and the next ten feet down.

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Re: Fouled hulls causing loss of speed

#5

Post by Tiornu » 16 Apr 2004, 07:48

The only info I have handy concerns the monitors Roberts and Abercrombie. For these fat-hulled ships, bottom fouling "translated into a loss of two knots after six months out of dock, while endurance would fall from 3600 miles to 2700 miles at 10 knots." (Fleets of World War II) For these ships, 2 knots represented a 15% drop. Please note that the rate of bottom fouling would vary; ships operating in the cold North Sea would not suffer as quickly as those operating from warm Pearl Harbor.

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#6

Post by Andy H » 28 Apr 2004, 20:44

Thank you both for your added comments.

I think it's important that when people start quoting stats at each other especially concerning ships, that they remember that all the figures given in most books, are 'ideal' in there nature. which as we know can be far from the truth at the given time of an event

Again thank you

Andy H

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#7

Post by Andy H » 28 Apr 2004, 20:46

Thank you both for your added comments.

I think it's important that when people start quoting stats at each other especially concerning ships, that they remember that all the figures given in most books, are 'ideal' in there nature. which as we know can be far from the truth at the given time of an event

Again thank you

Andy H

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