Beware of heavy chop, or waves, be very careful breathing as waves can sneak up on you right when you gasp for air, not fun. Bury you head down and try not to take breaths for a few strokes while swimming through waves, thats about all the advice I have for an ocean swim.-----
Swim Start: As for the rest, I assume its a beach start right? If so then, start on the beach in a ready position, run into the water at a good speed, not all out, swing your legs over the water while leaning forward. Dive in when the water hits your lower thighs, with a streamlined dive, you may want to practice this, remember to keep your hands together pointing forward with your head down tucked between you biceps. You may even want to practice this start with a 50 meter sprint or approximately 25-50 strokes depending on your stroke efficiency, right after your dive to simulate the start.
Breathing/Drafting/Sighting: After you have established your line in the water you may want to consider drafting, this will cut anywhere from 5-10% off your time, you can stay off someones heels or hips but if you dragging off the hips, don't get to far beside them as this will make the drag less efficient. Also remember when drafting off the hip, this will also slow them down, so a win win there, especially if your struggling to keep up. Some, or I should say, most athletes don't like to have you scraping the bottom of there feet on every stroke either, so give it a little distance, to where you can still see and feel the bubbles from there kick. Never swim side by side, both off you will be slowed and possible get your arms tangled. Drafting off the feet of another swimmer, prefferably larger with little kick is the most efficient. To swim a straight line its a good idea to adapt and alternate breathing pattern, meaning to be able to breath on both sides, this will balance your body and stroke. A good breathing technique is to, every 6-10 strokes, after you take a breath, trun your head slightly forward, with your eyes just above the surface, find your target and then continue on your regular breathing pattern. Remember when you do this, your lower body will naturallly sink in the water, slowing your down greatly, you can counter this with a strong kick while sighting in on you destination, or landmmark.
Swim Exit: As for the swim exit, at the end of your swim as you are getting ready to exit the water. Increase your kick to boost blood circ to your legs, prepping them for the next discipine. Swim until you can touch the bottom, stand up and your on your way, if it is still to deep to run, then dolpin dive(similar to the starting dive), till the water is at your knees. Its a good idea not to remove your goggles and cap till you get to T1, if you drop them in the water, then good luck finding them. Same for the wetsuit, don't undo the zipper till you are clear of the water, you will have a more efficient exit. If you practice these techniques in the pool and open water, you shouldn't run into anything you can't handle on race day. You mentioned a goal time for your swim based on a pool time, bad idea, throw your pool time away. You will have no idea of the conditions, start, or chaos at any particular swim start, you are right, there are many variables to consider. One thing you don't want to do is look at your watch at the end of your swim and be dissapointed as this may lead to demotivation or complete loss of your mental focus.
Notes: A couple more tips for your race day from my past experience, show up early, you don't need any panic to start your morning worrying about making it to the swim start on time...trust me. Oh, and stay away from fiber then night before and morning of. These 2 things I did successfully at my last race for the first time, and had the greatest race of my life. Just train hard, race harder, and most importantly, HAVE FUN! Good Luck!
-Anthony
