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Ex RTTL 2770

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2770 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 2770 Quote  Post ReplyReply Direct Link To This Post Posted: 09 April 2010 at 10:21am
New down-sized propellers. These proved useless and had to be changed as they gave an over-the-ground speed of 6 knots! The size was calculated by the manufacturer using a computer generated model. We in turn resorted to the old paper style calculation producing a propeller similar to the 60 ft GSP 2-1 reduction  23-1/2 x 23 prop. Our's were 24 x 24. The smaller props were retained as emergency spares.
 
The rudders were our own design with paddle fins for slow,tight maneuvering. Capable of being dropped off  to remove the props without slipping, this proved useful as we had to change the props.
 
New copper sheathing on the double diagonal as a protection against marine borers, toredo worm and zebra muscles. The triple skin was painted with SSBN (US Navy) anti-foul which kills absolutely everything trying to adhere to it. Dangerous stuff for sure. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 2770 Quote  Post ReplyReply Direct Link To This Post Posted: 09 April 2010 at 11:11am
[QUOTE=muffdiver]
 by hell the hour meters must have been around the clock twice over.
..........................................................................................................................................
 
Hi again Muffdiver. ( I have to laugh when I write your handle ).
 
On the machinery hour counters. We did not fit those,we did have some static bolt-on counters which worked by measuring vibration but they were never fitted. Only the harbor generator had one when we had Canadian Osprey, and that proved to be unreliable.
 
It is always better to work on recorded log times for maintenance than rely on vibro-counters.. By their very nature they tend to vibrate to destruction prematurely.
 
...........................................................................................................................................
 
Another point needing to be cleared up. I never re-named ex-2770 as Canadian Osprey, my late mother did.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 2770 Quote  Post ReplyReply Direct Link To This Post Posted: 09 April 2010 at 12:09pm
Below, forward section at time of purchase.
 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 2770 Quote  Post ReplyReply Direct Link To This Post Posted: 09 April 2010 at 12:16pm
Re-fit completed. Time taken - 11 months from purchase to launch. Cost to us at the time, minus purchase price, $49000.00 CAD.or thereby.
 
 
That's the last of the surviving photographs which I can find, if I find more I will post them. Somewhere there is a video diary covering most of her refit, ensuing boat work and re-enlistment venues for the USN. If I find it I will have it converted to DVD and post it online.
 
I do hope my info has been useful. Perhaps even filling a hazy chapter in the history of ex-2770 (Canadian Osprey)
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Post Options Post Options   Thanks (0) Thanks(0)   Quote muffdiver Quote  Post ReplyReply Direct Link To This Post Posted: 11 April 2010 at 2:11am
D2770 many thanks again for the recent pictures, they are priceless for the history of the vessel i quite agree the old traditional navy log was the best way to log the main engines,on the hour every hour and better than any mechanical meter reading, i am having difficulty reducing my HQ pics below 50 mb to upload to this web site, do you want me to e mail them PM,if so please let me know.
ps my handle is not as bad as you think !!!!
i have two versions of the above and are good at both !!!!
regards
Muff diver
Best Regards Charlie
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Post Options Post Options   Thanks (0) Thanks(0)   Quote rafwebfoot Quote  Post ReplyReply Direct Link To This Post Posted: 12 April 2010 at 8:11am
many thanks 2770 for the recunstruction pics and details.  How did she perform with the smaller props?  When in service she would have been fitted with 33" x 37.5" L/H props. which must have been a wee bit excessive for civilian use and unsuitable for anything other than the RR Sea Griffons.
FAIR WINDS AND A FAVOURABLE TIDE
Donald
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 2770 Quote  Post ReplyReply Direct Link To This Post Posted: 12 April 2010 at 11:30am
The props at 24x24 proved just fine.Giving an average of 12 - 15 knots O.T.G from memory. The sailing,machinery and diving compressor logs were all up to date when we parted company with her and should have been in the navigation case we passed on to the new owner, including machinery / electrical kit info manuals.. Consultation of the sailing logs will give the exact revs and speed achieved.... Please remember, we are well over 20 years on from her refit by us and I have done a mighty lot of sea miles since. 
 
Needless to say the props were handed.Those props were "Cut-Downs". The original size could still be on the boss as I cannot remember if they were re-stamped with the new size by the supplier. Had the originals been 24-25 pitch and handed we would have machined those down instead of replacing. However,although it can be done with difficulty, a pitch change was not an option.
 She could go harder at it depending on wind, tide and engine revolutions. However, I have never been one for caning main engines needlessly.1500 - 1800 RPM being just dandy. Without teaching others how to suck eggs,If you work the wind and tide to your advantage then the revs can be dropped considerably.
 
I have a personal strong dislike of twin or triple mono-directional props on hard chine planing / semi planing hulls, having been "Adhered" to the harbor walls and unable to paddle wheel off in gale force winds a few times. They were also quite useless on 2770 for our chosen work. Something which really surprised me, we offered Hendon all of the discarded fittings, machinery and electrical kit. Including the original RT. They declined the offer. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 2770 Quote  Post ReplyReply Direct Link To This Post Posted: 12 April 2010 at 12:34pm
Of any interest?
 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 2770 Quote  Post ReplyReply Direct Link To This Post Posted: 12 April 2010 at 12:36pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 2770 Quote  Post ReplyReply Direct Link To This Post Posted: 12 April 2010 at 12:39pm
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