Swim workouts for MBF one hour a week plan

Darren Miller during 2012 END-WET (27 mile river swim).  The event is my swim goal for 2013.  

Thought i'd provide some details about what exactly i'm doing in my one hour each week.  The earlier post laid out the basic form of my training schedule but left out the specifics.  I've also changed the schedule slightly - i'm still doing three 10 minute workouts a week (one swim, one bike, one run) but instead of having the longer weekend workout alternate between these three, i'm going to always make the longer workout a bike ride.  The apparent absurdity of trying to do the arrowhead135 in under 24 hours on what would have amounted to 1 hour of biking every 3 weeks finally got to me. It seems much more reasonable to make the attempt on what will now be 2 hours of biking every three weeks - don't you think?

But i'm getting ahead of myself - this post will focus on the three different 10 minute swim workouts that currently form my three week rotation.  I'll do one workout each monday afternoon, starting them over once i've hit em all, and always trying (but not always succeeding) to improve my performance from the identical workout three weeks prior.  After 12 weeks (4 cycles), i intend to change the interval schemes a bit to keep from stagnating. 

• Workout 1 (short intervals):  Main set - 6 x 50 yards, @ 35 sec; leaving every 45 sec.  
• Min 0-3:00 - 200 yd warm-up/cruising tempo
• Min 3:00-3:30 - rest
• Min 3:30-8:00 - Main set
• Min 8:00 - 8:30 - rest
• Min 8:30-10:00 - 100 yd warm down/cruising tempo
• Total - 10 min, 600 yards
• Workout 2 (med intervals): Main set - 3 x 200 yds, @ 2:30 - 2:35, leaving every 3:00 
• Min 0-9 - main set
• Min 9-10 - 50 yard warm down
• Total - 10 min, 650 yards
• Workout 3 (single interval):  Main set - 500 yard time trial
• Min 0-1:30 - 100 yd warm up, cruising tempo
• Min 1:30-2:30 rest
• Min 2:30 - 9+ 500 yd time trial (usually takes between 6:30 - 6:40
• Min 9:0-10:00 Warm down
• Total - 10 min, 650 yards