Mast tube and step details on a 2006 Sunfish

Wavedancer

Upside down?
Staff member
I thought it would be useful to show details of a mast tube on a 2006 Sunfish.

Background:
1. The thread started by milfordguy on the collapse of the mast tube (and step?) on his older (year?) Sunfish (http://www.sunfishforum.com/showthread.php?t=34216). Wayne followed up by referring to a prior thread (http://www.sunfishforum.com/showthread.php?t=31501) with much useful info, including pictures and advice on rebuilding a tube and connecting it to the deck. Because that particular boat was a Viking, a Sunfish clone of years gone by, I thought that it would be useful to also have documentation of a 'real', and more current, Sunfish.

2. I found out a few months ago that my 2006 fish had water sloshing inside the hull. Not good, to say it nicely, because I had been careful with my new toy and the boat had been out maybe twenty times in moderate breezes, and only a few times in heavy weather.

Finding the leak should be easy, right? Just do the soap bubble test. Well, I tried and tried again a week later, but no bubbles around potential trouble spots. However, upon the third try, I did see something suspicious near the top of the mast tube. Inspection showed some minute cracks where the flange of the mast tube is joined to the deck (http://kb.sunfishforum.com/images/construction/2.jpg).
This was in fact the problem area, because after filling up the tube to the top, the level would drop about an inch in a few hours and then stay at that level for many more hours. The hull was around 140 lbs, clearly a bit overweight for a 2006 specimen.
All of this meant that I had to put in at least one port to dry out the hull and possibly do a repair. It was a bit painful to cut a hole in the nice and shiny deck, but hey, it wasn't brain surgery. My suspicion was correct; there was water inside and the (white) structural foam felt damp. The (dark yellowish) expanding foam that holds the structural foam in place (the edges covered up with tape) felt clammy as well. After drying the hull in the sun, I took two pictures for the Forum. The first one focuses on the mast step, where the bottom of the tube is connected to the hull. It appears that the step is just extra layers of glass to secure the tube. I had expected a more elaborate structure as on the Laser, but no such thing.
The second picture shows the flange area of the mast tube. Note the (grey) ring that connects the flange to the deck. If you look carefully, you will see some white streaks; this must be 'stuff' leached out as a result of the leak. One can also see the glassed-in backing plates used to secure the halyard fairlead and cleat.

As stated, mine is a rather recent hull and the construction method shown may not be identical to the one(s?) used decades ago. Nevertheless, I hope that this thread is enlightening. Hopefully, others can fill in details that I missed.
 

Attachments

  • IMG_0417.jpg
    IMG_0417.jpg
    83 KB · Views: 98
  • IMG_0422.jpg
    IMG_0422.jpg
    107.7 KB · Views: 85
I'd give the factory a call. Much too soon and too much money to be having problems.
Might ask the following . . .

1. Will you fix free of charge or ship new hull?
2. If not 'Yes' on number one, what is the correct repair method?
2. What year did the change occur in the method of deck to mast tube attachment.
3. Did the new attachment method undergo 'Accelarated-Life-Testing' and if so what was the 'Time to Failure' estmate in years.

Kind of interested in #2. If what I'm guessing is epoxy putty starts to pull away from the deck, how would one reintablish the bond between the two?
 

Back
Top