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Mast Step

"Evidently, the idea was to give the boat all the weaknesses of deck-stepped mast and none of the advantages." S/V MOMO

The Baba/Panda/Tashiba 40 mast is not truly keel stepped. The load bearing surface was constructed from wood as a bridge and covered with fiberglass mat. This technique was also used on the Mason 43 and 44 and is prone to failure. Over time water seeps into the wood causing it to rot. The structure eventually collapses.  We noted that Veritas had been repaired on our first look. Bill Reynolds provided a photo of s/v Baidkara showing an example of the original structure. 

 


Swiftsure Yachts of Seattle provided following extract from the 2015 pre sale survey.

There is unbonded FRP tabbing and interior laminate fractures on the hull skin on both sides of the mast step. A previous repair has been conducted to the mast step but appears to have voids beneath the aft face from acoustical sounding. No information on the extent of the repair was available.

 

Recommendation: Pull the mast to gain full access. Open up the mast step to investigate further. Conduct full repairs as determined necessary to make sound. This is an ocean going vessel and is intended to be used for major offshore passage making. Conduct additional FRP repairs to interior hull skin and the loose and unbonded tabbing. Repaint the bilge area repaired and conduct any additional cosmetic repairs as necessary. Reinstall the mast.

 

The recommended work was performed by CSR in Seattle. However the invoice does not provide any details on the work performed. I contacted CSR and Scott Anderson responded via email with some general information:




On Jun 21, 2018, at 5:49 PM, Scott Anderson wrote:
Hi Myles
I can tell what we do to repair wood core mast steps. We remove all the wood and replace it with 1/4 G-10 fiberglass plates. We will stack them on top of each other until we get to the proper height. G-10 will not crush. Then we glass over the top. The delam in the photo could be injected with epoxy. Let me know if you have any questions. Scott


The 2018 pre sale survey findings stated the following.


THE AREA OF THE MAST STEP HAS BEEN REPAIRED AND THE SECONDARY BONDING HAS SEPARATED. REVIEW SERVICE RECORDS FOR DETAILS OF THE REPAIR. RE-TABBING THE SECONDARY BONDING IS RECOMMENDED.

We are finding the delimitation (or bonding separation) has occurred because the initial surface was never prepared properly in both the initial and secondary repairs. The layers of glass fiber/resin were applied directly to the inner hull surface without removing the gel coat and/or bilge paint from the inner surface of the hull. 

Found the following message on the Yahoo Baba-l list server:

From: keithessex
Date: Mon, 2 May 2011 19:51:38 -0800
Subject: Re: [baba-l] Mast step

Has any one had a problem with their mast step? I found our rigging had loosed after a passage. After noticing this I checked the Spartite on the mast collar and found it had settled a little over an inch and a quarter! I had Riggworks in San Diego tune the rig the day we left. The rigger was an Americas Cup racer, seemed knowledgeable but he didn't use a gauge. In my opinion he tighten the crap out of the rig like it was a high tech racer. There my be another underlying problem the caused this but I think the over-tentioning of the rig helped it along. Our Baba 40 was the last one made, 1996. It hasn't done a lot of sailing until we purchased it. I wouldn't expect a problem like this with a relatively young boat. Have any of you had a similar problem?
Keith
Nunatak, Tashiba 40

The wood bridge construction was replaced with solid wood blocks in this repair. We though this work was done by KKMI in Sausalito, CA in 2011.
However, after contacting Keith:

On Mar 22, 2019, at 4:03 PM, keith essex wrote:
It was done by a guy in Mazatlan.  He use to work in the yard at Maxatlan.  Don't know how to get a hold of him but I wouldn't use him again.
The second repair, by CSR in 2015, was done for Swiftsure Yachts. This work appears superficial. Several layers of glass roving and epoxy were added on top of the initial repair. The wood was not removed and replaced as intimated by CSR. As noted in the 2015 survey, voids exist beneath the aft surface of the repair. We opened this to check inside. We can see the wood inside the aft surface of the mast step and the supporting structure appears to be a solid block of wood. The wood is damp and shows some rot on the outer surface. However, it does not appear to have collapsed.

  

It is difficult to take pictures that clearly show the issues. We are trimming the failed tabbing back only to find that the original surface was not prepared properly. Most areas under the tabbing are still covered with gel coat and/or bilge paint. 

   

The best solution would be to completely remove the mast step down to the hull skin, it is not what we wanted to do. As long as the supporting structure appeared sound the plan was to redo the tabbing. The primary load is vertical and the lateral forces are minimal. By preparing the bonding surface properly and using a flexible epoxy resin the cracks are less likely to reappear. 



Unfortunately, I have obsessed for weeks avoiding the reality. The repairs of 2011 and 2015 were poorly done. This structure must be stable to be safe for extended offshore passages. I am looking at several alternatives, including splicing an extension on the mast to reach the keel. 
    
    

A decision was made. No gold was found. 

And the next step is to make a jig before the existing structure is removed. We will need it as a template to place mast shoe in the same location on the new structure. This will locate the position, height, and longitudinal angle with respect to the cabin sole.


A plate was also made to fit inside the mast collar and a hole was drilled in the geometric center for a plumb line. Because of the mast rake the shoe is about 2.2" forward of the mast collar. Annapolis Gelcoat and Fiberglass will be removing the old mast step and replacing it with a new one constructed of G-10. They went to work quickly.

  
    

It only took about 10 hours of work to remove the old step. You can see from the surfaces that it was not bonded well (if at all) to the hull. In fact, it is impossible to see where the original step was bonded to the hull. Additional surface prep is needed before the new structure is bonded in place. Also based on the working drawing it is probably good that we made our own jig as a second check. 

G-10 was then used to build a new structure similar to the original which was constructed from plywood. The individual pieces were glued into position. Glass was used over the structure to tab ti in place to the hull. Fairring compound and paint to make everything look nice. 
      






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