Monday, January 25, 2016

Alberg 30 Refit: Mast Step Repair

As mentioned in a recent post my Alberg 30 suffers from mast support compression. This is one major area on which I need to focus. 
I have begun some investigative work to determine the extent of the damage, starting with poking and drilling into the beam area. I was not too happy with some of the results. However, nothing so far seems to be irreparable.

I started by cutting a few lines into the damaged area. I used the oscillating tool for this.

As I was poking into the damaged area I found some very poorly laid up fiberglass. I did not chase this area all the way to its end, but I think it goes at least another 3 or 4 inches toward the starboard bulkhead.

Good news is that this poor fiberglass lay up appears to be only skin deep...literally. My 1971 Alberg 30 is what is known as a "liner" boat...meaning Whitby Boat works created a sort of "beauty" layer (similar to the headliner in a car) to enhance the appearance inside the boat and give it a more finished look. Without this liner you would see the bare fiberglass, which was probably a lot of work for them to clean and make presentable, so the liner simplified the finishing process. The damage so far appears to be a poor lay up of just the liner. 
Next, I drilled a few exploratory holes into the beam itself and I found the aluminum beam that is encased in the fiberglass. That is also good news. I suspected with all the compression that maybe the aluminum beam was a unicorn of sorts. Well, it's no myth; I located it. 

So why did the mast compress the deck? My answer is purely speculation but I believe quite plausible.  I have described my theory in the sequence of photos below:

In this photo you can see the mast step area (the actual mast step is a rectangle pad with 6 holes in it). Those holes are drilled into the deck. Over the years of hard use and poor maintenance, water seeped past those holes and into the balsa core below the mast step. Yes, there is balsa core below the mast step. I believe this was the major cause of the compression. Water got into the core, turned it into rotten mush and most of the integrity was lost.

I set the mast step pieces back on the step itself for this picture. This photo shows what I consider to be a major design flaw. The blue lines drawn on the deck outline where the support beam is in relation to the mast step. You can see it is not centered.  This likely caused some of the excess compression to the rear of the mast support down below. This will be redesigned when put back together.

Another shot of how off center the mast step is compared to the support beam down below. 

With everything all marked I began to cut into the deck. To no one's surprise I found soaking wet rotten core.

Not pretty.

Much to my relief, the rotten core did not extend much further aft than the mast step.

Further destruction.

Ah yes, just what I always wanted to do...cut up my poor sailboat. Ugh.

Area all cut open and lower skin exposed.

A shot from down below looking out.

At the end of the day this is what I cut away. 

This is not the best photo but you can see the compression in the center of the mast step area.  I will build this area back up with solid fiberglass and my favorite G10 board.

I have begun to formulate a plan. My plan will include re-designing and strengthening the mast beam and mast step area from both above and below.
This is a 3-in wide strip of 1/8th inch G10. I will fabricate a laminated beam in this area to assist in the support of the step. 

More on the re-design and strengthening of the mast support to come!


Here is a video I shot the day I cut the mast step open. 

When will I finally be able to stop destroying the boat I so dearly love?


  1. This will be great step by step instructions when I get around to doing the same repairs on my A30. I enjoy following your progress. Keep up the good work.

  2. This will be great step by step instructions when I get around to doing the same repairs on my A30. I enjoy following your progress. Keep up the good work.

  3. Hard job. What about your choice for electric prop? Electricyacht with QuietTorque may suit you.