Because the wind has been cancelled until further notice I wanted to find an exercise that mimicked the effects of a hard session on the body, so if we ever get any wind again I can make the most of it! Here's my idea.
Get yourself an old truck tyre and tie about 3mtrs of rope to it as if you were going to make a tyre swing. Cut a 700mm section of boom arm off an old boom (around the section you would hold on to). Thread the loose end of the rope through the boom to form a yoke, similar to the tail end of a ski rope.
Take this apparatis to the local oval. Drop the tyre on the ground, grab your section of boom as if your are going to hook in, bend the arms and walk backwards for a few laps of the oval. You will soon feel very much like you have been sailing for 2 hours in 25 knots!! The forearms burn, your fingers cramp up and your quads are on fire! If this is too easy for you, tie on another tyre!
Warning. You will get some strange looks. If you are, for example, like me, a 50yo grandad who trains in a pair of skins, don't try this at the local primary school oval. No-one will believe your explanation 
Hope this makes sense. I would post a photo but none of my kids is prepared to be seen taking a photo for me
@wet willy, the more elbow bends you do the more weight you pack on therefore it should be easier to hold down a sail in big winds
Would love to see the photos mate
Becuase I'm an old fart too, I have just started a weights program at home in the hope of improving my core strength. Started about 4 weeks ago and encouraged so far by results. Real test will be in a few months when the wind comes 
simple exercises like push ups, situps, chin ups will cover all the bases, start by doing 5 of each.
reverse grip chin ups and close grip chin ups. Burn like hell after 5 reps and make my personnel training laugh hard at the facial expressions that result.
That said they give the arms, shoulders and back a real working in exactly the same muscles are sailing.
Fit balls the go to. Anything that works your core muscles really seemed to help last season. The exercise are strange and look weird and usually really work you over but it is amazing how weak your core is when you start out.
Just get a SUP and start paddling You could still wear tight fitting lycra if you wanted to
Try the Deadlift.
A simple exercise, which is considered one of the best ways to strengthen core/lower back and legs.
I spend any where between 9 and 14 minutes per day for a session. Start with a low weight, increase reps during the week and increase weight over the weeks.
Had my first sail in 16 weeks the other weekend. Wind was 15-25knots, and sailed for over 1 and a 1/2 hours.
Absolutely no stiff and/or sore muscles whatsoever that night or over the next few days.
I highly recommend it.
Cheers!
now im not very smart but i can lift heavy things.get a job lifting heavy things & if your back doesnt go your always in training for windsurfing & PEOPLE WILL PAY YOU FOR IT 
If you want a formal exercise then push-ups are about as good as they come. All the muscles that need working will get worked. If you can do push ups with good form you can do anything.
Bugger.. not having the muscles of you blokes I can only manage 1 crummy one.
.Might have to check with the chiro if its ok to try & do some..
You could still wear tight fitting lycra if you wanted to
I do something like this...
1.Jumping rope for 5 min
2. made a simulation of windsurf position... 2 ropes tied to ends of a steel bar (or boom residual) and hung on a higher position (can be fixed to a ceiling), then I pus something on the floor to fix my heels and position myself holding the bar, feet on the floor fixation and almost laying down with body straightened , then do 10-15 pull-ups
3. 15 push -ups
4. 20 situps
5. repeat everything 2x more,without jumpiung rope.
This helped me being able to surf 5h straight or more in 20-30 knots without sore muscles or getting cramps... didn't help much in loosing weight though XD I still eat and drink too much beer :P
2 weeks of everyday exercising got me going much better, no more hammers because of cramps or weak leg strength, no cramps in biceps...
I've been doing my tyre dragging excercise for about a week now so I have posted a pic of my progress
