Mast Step Repair

Way back during the original pre-purchase survey, some corrosion of Circes' mast step had been noted. The discovery was useful in the sales negotiation but we knew the repair would be a major event so we let it slip behind other projects while we did everything necessary so we could live aboard in comfort. After that we got distracted with some other issues and, before we knew it, 5 years had zipped by..........out of sight, out of mind? It was past time to address this critical area and we hoped it would be the last big ticket project in Circes' rehab.

Here is a shot of some large flakes of rust that had fallen off the underside of the mast step. Access to the step is very poor but we could see enough to know it was heavily corroded. It was a black iron weldment that may have been painted or galvanised originally, but there was no sign of any protection left. Not the best material for service in a wet environment, particularly with no provision for complete drainage of the water coming down the mast. Frankly we were surprised it had held up as well as it did for over 30 years! 

From our research it appears the mast step is a weak point on Freeports, with numerous other boats of Circes' vintage having similar corrosion issues, varying from moderate to terminal. Pictured left is an example of the latter. That paper thin upper plate was originally 3/8" thick!

Freeports came in two flavours called 'A Plan' and 'B Plan'. The mast on A Plan Freeports, shown here, is out in the open in the main cabin and the mast step is fairly easy to access, inspect and maintain but.........

........but, in complete contrast, the mast step on B Plan Freeports has extremely poor access. It is completely buried under the cabin sole behind the main centre bulkhead cabinetry and the mast itself is fully enclosed on all sides from floor to ceiling. Here is the view from the Main Cabin side.

Here it is from the Pullman side. To get working access to the mast step the cabin door and the locker under the Pullman Berth must be removed and then some of the mast casing cabinetry and part of the sole has to be cut away. All the cabinetry is integral to both the main centre bulkhead and the Pullman Berth so opening things up and replacing them without leaving unsightly scars is a real challenge! Thanks to the efforts of other Freeport owners who have replaced their B Plan mast step, there is plenty of info and photos on the FOGgers website showing how the cabinetry is put together and how best to take it apart. We used some of those images to plan our attack! 






Obviously the mast needed to be pulled out to allow for this repair and, because we have had good past experiences with them, we arranged for Hansen Rigging in Alameda to pull it and also replace a few items on the standing rigging while it was out. We also planned for a new paint job. But, before we rushed off to the boatyard we wanted to do as much prep work as we could in our slip as we knew the biggest chore would be doing the necessary surgery on the sole and the cabinetry surrounding the base of the mast. 

First we needed to remove the storage locker under the Pullman Berth. That actually went quite smoothly. We removed the locker door (although it could easily have been left in place) and emptied the drawers under the berth to protect clothing items from dust and dirt. Then we removed the (10) screws inside the locker, along the back edge of the locker lid. Next we drilled out the (4) plugs in the front edge of the locker lid and removed those screws. The locker lid then lifted off in one piece. 

Next we removed the (6) screws in the cleats holding down the facade to the sole and then the whole front of the storage locker lifted out in one piece.   

Next we had to decide on a suitable way to section the lower part of the mast casing so it could be easily removed and replaced for this and any future projects involving the mast base and step. To give ourselves the best chance to camouflage the necessary cuts we decided to align them with the edge of the door jamb (vertical) and the top edge of the locker lid (horizontal) under the Pullman berth. Shown here is the line where the oiled wood ends and where the top of the locker lid sat below the Pullman berth. This was our chosen spot.

Here we have taped and marked the area to be cut.

Here is a shot of the simple guide we made from a scrap piece of 3/4" aluminium angle to guide the Dremel blade and give us a nice clean straight cut. 

And here is the finished cut. We moved the guide around from side to side to make sure the horizontal cuts were square and straight. We used an old steel rule clamped to the door jamb to keep the vertical cut straight. Keeping the cuts clean and square was important for a presentable appearance when we reassemble things.

There were numerous screws inside the locker holding the mast casing back against the berth bulkhead. When the lower two screws were removed we were able to slide our sectioned piece of casing away from the mast. To minimise the scars and simplify the cabinetry replacement process we made a point of not cutting the door jamb.

This shot shows how the sectioned mast casing came out in one nice clean piece, which will make life a lot easier when we put everything back together.   

Next we shifted our attention to the sole. To access the mast step we had to cut out a couple of large sections of sole forward of the mast, parts of which were sitting directly on top of the mast step. In order to make reassembly a bit easier we chose a spot in line with the forward edge of the centre floor hatch for the transverse cut. Using that spot means there should only be a few inches of the cut visible when the sole and locker are replaced.....we hope! There was an existing joint in the sole on the centre line of the boat, so there was no length-wise cut needed to remove this first piece. When it was lifted out the starboard side of the mast step was revealed.

Now we could really see the extent of the corrosion. Clearly visible here is the severe pitting on the top plate of the mast step and the distortion of the sole caused by the growth of ferrous oxide pushing up against the underside of the sole. A distinct bend can be seen in the plywood.

A sharp jab with a screwdriver caused a huge chunk of the corner of the mast step base to break off.......scary to think the whole rig is sitting on this! 











To expose the port side of the step we needed to cut out another piece of the sole, but before we could do that we needed to cut down the inner locker divider, the unfinished piece of raw plywood to the right of the mast in this pic.

We chopped off the lower 8" of the divider to remove damaged wood and improve access to the sole. With the divider cut we could also see the full extent of damage caused by the battery acid spillage (admitted to by the PO) due to the absence of a proper battery box. We had been aware of the problem and had already repaired a small section of floor at the step down into the Pullman area (see first pic in this post) but we hadn't seen exactly how far the damage extended under the sole and the berth. It was ugly. Several pieces of new ply will have to be spliced in when we reassemble everything. 

Now we had enough access to remove the second piece of the sole. Here we've cut beyond the centre line and exposed the port side of the mast step.  At this point we had fully exposed the sides and forward part of the mast step and the forward support stringer. To expose the aft side of the step and the aft support stringer we needed to remove the batteries and battery box which are located under the dinette seats. We decided we would do that step in the yard, after the mast has been pulled, so, off to the yard we went. 

Here the sails and boom have been removed, the standing rigging and headsail furler are disconnected and the mast is starting to emerge into the light of day.

In this one the crane has lifted the mast up onto the dock.















These next two shots show the mast base corrosion and how the aluminium shoe disintegrated as the mast was being lifted out. This highlights another fundamental design/build issue. Bolting aluminum directly to iron with stainless fasteners and then regularly soaking it with water is a sure recipe for big corrosion issues. At the very least there should have been a non-metallic isolating spacer between the shoe and step.

The corrosion had welded the aluminum mast shoe to the butt of the mast and the bottom two inches of the mast extrusion were also severely damaged.

To get back to good metal 1 3/4"  was cut off the bottom of the mast extrusion. Also visible here is what was left of the shoe.

Something seems to be missing?

With the mast out and the forward part of the step exposed we shifted our attention to the aft side of the step. First we had to remove the house battery bank (two L 16's) which are located right next to the mast step under the dinette seats. 

Because we live aboard full time and need the house batteries connected, we made up some 2/0 extension cables 4 feet long so we could relocate the batteries temporarily to the floor in the dinette. Here are the cables waiting to be installed. 

Here are the batteries sitting on the floor in the dinette area. We routed the cables through an existing vent hole so we could keep the dinette cushions in place.

Living around the batteries for a month was very inconvenient, and we couldn't use the table, but it allowed us to keep everything operating.

With the batteries out we were able to look closely at the floor under the battery box and saw that it was badly damaged due to the previously mentioned acid spill by the PO. We decided to cut it all out and replace it with fresh wood treated with penetrating epoxy to protect against any future spills. Here we've got half of the floor out and there is now access to the aft side of the step.






Next we used the Dremel to cut the resin all around all the edges and both ends of the mast step weldment to free it from the stringers. This shot shows the forward end of the mast step after the cutting.....so far so good. To this point everything had gone pretty much to plan..... that was about to change.  











After the cutting we jacked the weldment up and out of the stringers, revealing........

 







.......revealing first, the good news.......the forward stringer core was solid and undamaged with no sign of rot.

Next to be revealed was the bad news......the aft stringer core was completely rotted away. We could see where water had seeped between the weldment and the fibreglass skin of the stringer and into the core. We drilled some test holes along the stringer and found the rot extended all the way out to the limber holes on both sides. The leak into the core had been going on for years. The only thing supporting the aft end of the mast step had been the 1/4" thick stringer skin!!

Here we've opened up the starboard side of the aft stringer skin showing the full extent of the problem. The plywood was just mush!!

And here is the same mushy wood problem on the port side of the stringer.

Here we've cleaned out all the rotted core on the starboard side. 

We did the same on the port side and.......

.....and then we replaced the core with fresh wood. In this shot the complete aft stringer core has been replaced, re-bedded with thickened resin and the skin has been re-glassed.

Up to this point we had been planning to simply replace the corroded mast step with a similar design, but built with stainless steel, and use a thin phenolic isolation plate between the step and a new shoe. Other Freeport owners have done this. Things were complicated by the fact we couldn't source a correct replacement cast aluminium shoe for the LeFiell OM4C mast extrusion. This pic shows a new shoe from a step repair done on a sister vessel some years back. After a couple of phone calls it appeared that LeFiell had 'suspended' the Marine Products side of their business and no new LeFiell shoe was in our immediate future. Whether the business suspension is temporary, pending a divestiture or a permanent closure isn't clear.




A further complication was our concern that the original step design was obviously vulnerable to leakage at the joint between the weldment and the support stringers.  Even if Circes' original mast step weldment had been stainless, the aft stringer core would still have rotted out due to leakage at the joint. We consulted several knowledgeable sources including a boat builder and a marine architect and decided to go another way. Synthetic stringer core material has been used with some success on other boats, and that was briefly considered, but we had already replaced our rotted aft stringer with wood, and the forward one was also wood and was in good shape so that wasn't a realistic option. 

After further research and discussion with the pros we elected to completely eliminate the weldment and build a composite, solid longitudinal support block between the two stringers. It would be the same width as the old step weldment and would be tabbed to both of the stringers and extended down to the hull. A one piece custom combination mast step/shoe in anodised aluminium would be mounted directly onto the block, eliminating the separate step and shoe, plus the complication of joining dissimilar metals. The consensus was that it would be a simple and rugged solution. 

So, here is the new step. The block is a vacuum bagged laminate of Hydrotek marine ply, glassed over and extensively tabbed between the stringers and the hull over the keel. 

Here is the new anodised aluminium combo shoe/base assembly being test fitted. Also visible is the 1 3/4" spacer plate underneath it, compensating for the badly corroded metal that was cut off the base of the mast extrusion.

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In this one we are test fitting the sole boards that had to be modified to suit the new step arrangement.

At this point we were waiting for the mast to be re-painted, the new standing rigging to be built and a couple of running rigging upgrades to be done, so we started to replace the sole under the dinette seats where the house batteries sit. We used 3/4" Hydrotek saturated with penetrating epoxy.






We were unexpectedly delayed for 2 weeks due to the yard experiencing problems sourcing their preferred materials to paint the mast. Recent changes in California Hazmat regulations had changed how and where certain paint products are distributed, sold and used, making it difficult to get the right products........which (of course) are freely available elsewhere in the US! The California eco-freaks strike again!

While waiting we also pulled the mast collar at the partners, had it powder coated and re-bedded it with butyl mastic.....our preferred bedding material. There was no sign of rot in the deck core at the partners but we treated it with penetrating epoxy anyway. 

Finally the mast was reassembled and the rigging changes completed, so re-installation could begin. Here the crane is positioning the mast ready to drop it back into the boat. 

           There she goes and.........

.....and here she comes.

                 Touch Down......!

We thought that the single bolt through the mast and collar at the partners was a bit marginal for mast control so we went ahead and added a full set of chocks to positively locate it. We've noticed a significant reduction in mast pumping since we did this.

Everything back together and looking good. To provide some redundancy in the rig support, and to simplify tuning the (future) SSB antenna, we converted the single split backstay to twin back stays. One will be fitted with insulators when we get the new SSB. We adjusted the new backstay set up to get a little more mast pre-bend than we had previously. We've always felt we could improve the mainsail shape with a bit more mast bend but never got around to adjusting it. This project allowed us to get it done. 










 
Stay tuned for an update to be published when all the cabinetry is back together. 
Later...... 

Update 2 - 23 - 16

With the boat back at our slip we started in on repairing the sole and replacing all the cabinetry. The first step was to replace the undamaged sole on the starboard side of the mast step. We stripped the varnish from it and we will refinish the whole sole in the Pullman area when we are done.













The next thing was to make a new piece to replace the sole that had been destroyed by battery acid and water damage. First we templated the area  with poster board, then with 1/8" ply and finally we made a new sole insert from 3/4" Hydrotek. This shot shows the ply template.

Here the Hydrotek has been cut and stained and we've slathered penetrating epoxy on it.  

And here is the new piece of sole in place. We considered covering it with a piece of teak and holly veneer to match the existing sole but decided that so little of it would be visible that the cost didn't make sense. 

Next up was to replace the acid damaged lower edge of the centre bulkhead. One again we used Hydrotek soaked in penetrating epoxy. We also added a couple of cleats to stiffen things up. 

Then we replaced the piece of locker divider that we had chopped off to improve access to the step.

To give ourselves an easily removable cover for future access to the mast base we made some cleats and fitted them to the mast casing. 

Here is the (now removable) piece of lower casing back in place. We debated making trim strips to disguise the joint but it is a clean edge in such an unobtrusive spot behind the door we finally settled on simple screws with finishing washers. 

Here the locker is back in place. There is only a very small area of the un-veneered sole visible and with everything stained and varnished it blends in pretty well. Glad this project is finally done....it was a biggie!