Well, you could call youself an "old yarder," you think?  <;-)

Actually, if I'm readin' the online Oxford English Dictionary correctly, the term doesn't seem to have anything to do with sail rigs, see extract below.  Sounds like you may already be a gaffer, never mind your rig.

.....Michael

gaffer, n.

Brit. /ˈɡafə/, 

U.S. /ˈɡæfər/

Forms:  Also 15, 17 gaffar.

Etymology: The analogy of the continental synonyms, French compère, commère, German gevatter, would suggest that gaffer, gammer are contractions of godfather, godmother rather than of grandfather, -mother; but the change of vowel may be due to association with these words.

 1. A term applied originally by country people to an elderly man or one whose position entitled him to respect.

 a. Prefixed by way of respect (sometimes with an affectation of rusticity) to a proper name, the designation of a calling, office, etc. In 17–18th centuries the usual prefix, in rustic speech, to the name of a man below the rank of those addressed as ‘Master’ (cf. goodman n.).

 b. Used simply as a title of address, often with no intimation of respect = my good fellow.

2. An elderly rustic; an old fellow. Also simply, a fellow.

3.

 a. A master, a ‘governor’. Obsolete exc. dialect.

 b. The foreman or overman of a gang of workmen; a headman.

Ha!  Thanks Michael.  I didn't actually think of looking up the definition.  That's good stuff!  It'll give me something to ponder today at work...

It's your t-shirt, put whatever you want on it. It's not like someone's going to sue you.

But if you think that 49 is old, you are SO in for a shock when you pass 60! :-)

Laszlo

PS - my t-shirt says "Registered Sexegenarian"

Laszlo, it's SO funny that you mention t-shirts.  I actually do make t-shirts like that.

Some of my best are:

14,610 Days Scurvy Free (you do the math)

The sunset is in my eyes, this beer is too cold and who are all these naked women?

Sailing Upwind Sucks, Sailing Downwind Blows...

I'm Why Roger is So Jolly (for the ladies)

And here's my graphic for the divers' charters I used to do in the BVI

   What do you think?