Peter,
Take it from a H17 owner - these are a pain to tack w/o a jib. A
couple of the people got it basically right. The key is to ease the
main as you come head to wind. The windage is high on these boats and
the mass of the craft is low so it slows down real fast when pointing
into the wind. Also the center of effort is well aft so the boat will
'weather vane' dead into the wind if you don't ease the main.

My technique was to:

1: keep the mail close hauled as you head up into the wind
2: release the main as you come through the wind. I like to 'help' the
main ease out as the boat rounds over to the new tack but don't
backwind the sail
3: fall off to a close reach
4: gradually sheet in the main. The boat will point up as you do this
(no matter what you do with the rudders) - the sail has more influence
on headding as these low boat speeds
5: as boat speed increases the rudders will bite again and if you
played it right you will now be on your desired close hauled course.

Just remember that in an H17 w/o a jib that at low boat speeds that the
main will be the more importand 'rudder'

Easy enough, right?

After 5 years perfecting my tacks on my H17 I installed a jib kit
this year. Once the challenge is gone tacking a H17 w/o a jib is just
a pain.

Enjoy learning a new style of sailing

Bill