This program is a beginner plan to bridge you from an a Half Ironman to Ironman using a HRM with the confidence that you can complete the race without difficulty.
Executing this full Ironman plan for 17 weeks would give people with one Ironman under their belts very good preparation for a 2nd and 3rd. Preferably, you should have a 6:30 or faster HIM time.
This Intermediate 20 week plan is a quick ramp up in overall volume, but with 20 weeks to train only, it is a gradual and safe approach because of the alternating weeks of the long run/bike.