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S&S Swan Maintenance - Mast step corrosion
13 January 2019 - 21:48
#1
Join Date: 09 December 2018
Posts: 4

Mast step corrosion

Dear Lars,

can i remove the corroded mast step and make a new one of C 10 epoxy resin?

What's undernith the corroded plate? solid fiberglass?

 Andrea Centaro, 43-028 Hyperion of Turku 1971

p.s. the mast shoe is in good condition

14 January 2019 - 06:45
#2
Join Date: 02 January 2008
Posts: 1306

Dear Andrea

Yes, you can remove the mast step, and there is solid GRP under it. Removal needs some brute force, the holes could be used for for lifting.
There appears to be drain holes at the bottom of the step, important to include them in the new one also. 
The holes each end are intended for screws enabling longitudinal adjustment of the mast position. If you do not need adjustment it is sufficient to put in spacers forward and aft, can be of the same material as the new step.
Is there a vertical drain hole in the mast shoe? If not, the recommendation is to make one. The bigger the better, this improves ventilation of the bilge.
Kind regards
Lars

14 January 2019 - 22:03
#3
Join Date: 09 December 2018
Posts: 4

Dear Andrea

Yes, you can remove the mast step, and there is solid GRP under it. Removal needs some brute force, the holes could be used for for lifting.
There appears to be drain holes at the bottom of the step, important to include them in the new one also. 
The holes each end are intended for screws enabling longitudinal adjustment of the mast position. If you do not need adjustment it is sufficient to put in spacers forward and aft, can be of the same material as the new step.
Is there a vertical drain hole in the mast shoe? If not, the recommendation is to make one. The bigger the better, this improves ventilation of the bilge.
Kind regards
Lars

Thank you Lars for your answer. Which holes can i use to lift the plate up? The drain holes or the forward and aft adjastment holes? Also i would like to ask you: is the iron step glued with resin to the solid fiberglass?

About the mast shoe yes there are two drainig holes.

Thank you again, I'll let you know how the work will go.

Best reguards

Andrea

15 January 2019 - 15:48
#4
Join Date: 02 January 2008
Posts: 1306

Dear Andrea

The adjustment holes are better for lifting.
The step is laid down onto wet resin, but the bonding to steel is not very strong.
It is suggested you first try to break the bond by hitting the step ends with a sledge hammer, or better putting a steel bar in between to enable the hammer to swing, and then lift.
Would appreciate to hear how much effort was needed
Kind regards
Lars

20 January 2019 - 23:02
#5
Join Date: 09 December 2018
Posts: 4

Dear Lars,

as you suggested I tried to remove the mast step using a sledge hammer and after a chisel than tried to lift but I think that the mast step is one piece with the longitudinal iron "C" shaped structure (two longitudinal bars and flor with a keel bolt on the forward end). I don't think the central step can be removed without the whole strutture. Glad to hear from you , Andrea, 43/28 Hyperion of Turku

21 January 2019 - 15:02
#6
Join Date: 02 January 2008
Posts: 1306

Dear Andrea

Nice sketch! I thought the steel beam in your first photos ended at the floors, but now I know better. It is necessary to open the keel bolt nut forward, and cut loose the matting in of the steel beam on the outside along the lower edges.
Then you could attempt wedging the beam loose from each end.
I would suggest a slightly different approach for the new floors of epoxy plate. They should be attached to the bottom along their entire lower edge, with just small limber holes at the lower corners, and a bigger hole at half height for the hoses. They can be glued in place.
If this is OK with you I can make a sketch.
The mast is well supported on the keel, but the area between the forward end of the keel and the bulkhead should be checked carefully for signs of movement. If there are problems this could be remedied at the same time.
Kind regards
Lars 

21 January 2019 - 17:23
#7
Join Date: 09 December 2018
Posts: 4

Thank you Lars, I would appreciate a your sketch to work under your guide. About the bulkhead yes there are signs of movements like an old vertical crack next the door opening and more recent crack down below on the bulkhead fastening occurred after a very bad slamming in rough sea. I'll keep you up to date and I'll send you photos. Thank you again Andrea, 43/28 Hyperion of Turku  

22 January 2019 - 14:31
#8
Join Date: 02 January 2008
Posts: 1306

Dear Andrea

Enclosed pls find the sketch. By adding a horizontal flange on the top - at the same time floorboard support - the strength can be increased considerably. The upper and lower edges of the floor vertical part are tapered for providing bigger bonding areas.
Thickened epoxy is needed, enabling fillets with 25 mm radius to be made along the joints.
It would be good to locate the new floors halfway between the keel bolt pairs, this means their number is increased. How many floors would there be with such an arrangement ?
What is the specification for the epoxy sheet, and what thicknesses are available?
Kind regards
Lars

 

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