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S&S Swan General - Swan 57/037 Bianca di Navarra complete refit
04 June 2021 - 16:58
#1
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BLUE ITHACA
Join Date: 16 April 2021
Posts: 18

Swan 57/037 Bianca di Navarra complete refit

I have just started a complete refit of the Swan 57 Bianca di Navarra. Before all I decided to sand blust the hull to remove many years of antifouling and have a look at the gel coat. It has been a good idea indeed as I had a quite unusual surpise...

Does any body have an idea of the meaning of the perfect squared holes filled with foam I found in the keel ? Was the only for lighten the boat?

sundblast protection

the hole

holes
04 June 2021 - 17:00
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BLUE ITHACA
Join Date: 16 April 2021
Posts: 18

more photos
04 June 2021 - 17:07
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matteosalamon
Join Date: 29 January 2007
Posts: 1019

Dear Blue Ithaca,

keel has been redrawn and made thicker, after original design, but total weight remain the same, therefore the two holes.

Fair winds!

matteo (47/069 Vanessa) m 
04 June 2021 - 17:10
#4
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matteosalamon
Join Date: 29 January 2007
Posts: 1019

PS I hope The Professor could remember when the keel has been redrawn, probably before launching the very first boat. I think S&S Swan 57/028 only has filled pockets.

Fair winds!

matteo (47/069 Vanessa)
05 June 2021 - 08:07
#5
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the professor
Join Date: 02 January 2008
Posts: 1547

Dear Matteo and Blue Ithaca

As far as i can remember the keel drawing from S&S showed the square holes, intended to enable trim and stability adjustment.
Referring to the bottom gelcoat, please note that it is unpigmented and transparent. Be careful not to grind away this layer, it gives additional protection
Kind regards
Lars
06 June 2021 - 11:15
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BLUE ITHACA
Join Date: 16 April 2021
Posts: 18

Thanks a lot Lars.

I will update on the works in progress
08 June 2021 - 16:04
#7
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BLUE ITHACA
Join Date: 16 April 2021
Posts: 18

Good evening Lars.

In the pictures attacched You will see in details the situation of Bianca di Navarra's keel.

If i well understood the holes had been made at Nautors shipyard during the construction and that this holes were supposemto be free from the keel coverage with special protection and antifouling, so that water cen pass tre... It sond a little weired.

The holes actually were filled with foam (possibly thermantus) completely soaked of water.

The only thing that worries me a little is that an internal face of the bow hole is cracked. The crack is not so deep but there it is.

I will decide with the yard how to cope with this crack, while the holes will be filled with closed cells light material.

Any further advise?

Thanks

Camillo

 

 

 
09 June 2021 - 06:04
#8
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the professor
Join Date: 02 January 2008
Posts: 1547

Dear Camillo

Thank you for the information
Referring to the forward hole, it appears the forward edge is slightly bent, probably the result of the keel hitting something.
It would be advisable to reinforce the forward edge by bolting a stainless plate over the crack.
Kind regards
Lars
09 June 2021 - 12:40
#9
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BLUE ITHACA
Join Date: 16 April 2021
Posts: 18

Thanks a lot Lars.

Sorry for the horrible english of my pevious post, written with a cell phone...

I will follow your advice and let you know how we will reinforce the hull

Camillo
13 June 2021 - 19:02
#10
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swanlake57
Join Date: 01 May 2017
Posts: 16

I am surprised that a hull that late in the production run (37 of 49) would have the steel plates installed. Do you think they are a retrofit after production or, original when the boat was built? Be interested to know what bolt pattern is associated with this hull. When we refit the hull on Swanlake we also had the plates but, they look to have been installed post boat construction. 
15 June 2021 - 06:40
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the professor
Join Date: 02 January 2008
Posts: 1547

Dear swanlake

According to the drawings the early boats had keel bolts instead of the plates, but the GRP plinth was too narrow for them, and from 023 the plates were installed instead.
Kind regards
Lars
15 June 2021 - 11:47
#12
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BLUE ITHACA
Join Date: 16 April 2021
Posts: 18

Dear all 

thank you for the interesting and comforting notes. 

 
30 October 2021 - 15:41
#13
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BLUE ITHACA
Join Date: 16 April 2021
Posts: 18

I will add the original drawing of the keel and some picture of the works in progres

original keel drawing by Nautor

keel bolts

ready for lamination
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