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S&S Swan Maintenance - Hull to deck join
07 January 2018 - 22:06
#1
Join Date: 19 July 2007
Posts: 66

Hull to deck join

Hi All.

Has anyone got a sketch, or drawing of a cross section of the construction of the hull to deck joint on a 411.

I have some stress cracks on the inner corner of the join adjacent to the toe rail fixing bolts. before removing the brown flocoat to expose the laminate i would like to understand the details of the joint.

Many Thanks

Paul.

Hierro 411 042

08 January 2018 - 11:59
#2
Join Date: 02 January 2008
Posts: 1547

Dear Paul

Here a detail from the Swan 36 General Specification found on the Association website.
The newer models have the same arrangement: the hull upper edge has a horizontal flange onto which the deck is thru bolted, and the joint covered by a wooden or aluminum rail. 
What you see is likely to be the inner edge of the hull flange trying to separate from the deck. It is known that shrinkage effects when moulding the hull can cause the flange to distort slightly. This is a cosmetic issue.
Kind regards
Lars

08 January 2018 - 21:22
#3
Join Date: 19 July 2007
Posts: 66

Dear Lars.

Thank you for your reply. Am I correct, that the toe rail fixing screws are bedded with a mastic sealant and no other insulation material?

Regards

Paul.

09 January 2018 - 13:37
#4
Join Date: 02 January 2008
Posts: 1547

Dear Paul
You are right about the screws, there is no separate insulation layer. It was assumed that the toe rail anodization would prevent corrosion, it is a very good insulator, but in practice tightening the screws tends to damage the anodization, 
If there now are crevices around the screws water will collect in them, and cause continuing galvanic corrosion. It could be tried to fill the crevices with a zinc-rich paint like International Interzinc 22 to keep the water out. 
Kind regards 
Lars

25 January 2018 - 21:24
#5
Join Date: 11 November 2017
Posts: 25

Dear professor, 

 

Is the joint similar in 37 also? Pohjanneito has an aluminium toe rail.

 

She has a small leak between Galley and SB bunk near toe rail. The water is very salty.

26 January 2018 - 09:41
#6
Join Date: 02 January 2008
Posts: 1547

Dear JereQ
Your joint is similar, with the bolts also going through the aluminium.
Your yacht had the aluminium rail added later. Only the four last 37¨s had aluminium rails when built.
Try to blow air into the leak, and put soap water in the suspect areas for locating the source.
Kind regards
Lars

 

26 January 2018 - 18:14
#7
Join Date: 11 November 2017
Posts: 25

Dear Professor, 

 

Thank you very much! 

 

Jere Q

 

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