It sounds like you already know what any 'veterans' may know - and it's just a matter of practicing and getting comfortable with what you have learned.

For myself, I made my best paddling advances starting last Summer by paddling in weekly sprint races.  I'm a distance guy and always trained for distance by steady paddling with some sprints involved.  But when I got into some serious sprint races I was amazed at how much it helped my distance paddling.

Not a paddle technique thing but for a race like the MR, I will add that another way to be most efficient is to test everything.  And I mean everything.   Putting on a new pair of sunglasses that pinch your nose just a bit too tightly is an annoyance .... Until you paddle past Miami and the pain on your nose starts to take you out of the race.  Test your boat as it will be fully rigged for the MR to make sure you can reach what you need and that it's balanced as best it can be fore and aft. Only carry what you need between each checkpoint stop.  Stuff like that.

The best advice I got was to sign up for the Freedom race and the Shootout.  I had never been on the Missouri river before and doing those races helped my confidence a ton. 

I don't know where you're located, but if schedule and logistics allow, I would highly recommend them. 

The Shootout is basically the first leg of the 340. The Freedom race starts on the Lamine river and ends at Jeff City.  By the time I had done those two races, I had a little bit more idea what the river was like, how the buoys and channel markers worked, what it was like to meet a barge on the river, and most importantly, if I was on the right track with what I had in the boat and where everything was stowed.

MurKee Water wrote on 01/07/18 at 20:59:54:


There is a a downside to a faster boat. When you start reaching the higher speeds you really start thinking about finishing times. This means you start doing things to get your time lowered even more.The first item that is jettisoned is SLEEP. This is the reason a paddler needs some good shakedown races to learn the speed of his/her setup and plan accordingly.

DLJ

Fred- Of course if you are as delusional as my human none of this matters. 

Do a long day 120 miles or so a month before the race.  That will have you paddling in the dark as well as the light.  Take care of your bottom.  The person who said to test run everything was right.  That means test out the skivvies you will wear and your seat pad (if any) too.  Practice.  Realize that if you are wet, everything will change including location of blisters.  Do not wait to put on sunscreen or to adjust a water valve that is not working up to what it should.  But as you get tired, don't give yourself too many excuses to stop paddling for a minute or two.  Pace yourself.

I agree with Murkee, there is a lot of mental toughness that goes into this race.  If you are in relatively good shape your body can complete this race barring injury.  A lot of people bow out of the race because of the mental aspect of the race. If you run this race there WILL be a time you contemplate quitting. I have seen many people say NEVER quit on the water.  Hit the bank give it 30min-1hr and then decide. 
Something I haven't seen answered here yet is mental toughness pertaining to Tandems or teams.  It is imperative to get on the same page as your partner. You also have to know your partner well enough to handle any issues that come up.  I've been blessed with a couple of great partners so I haven't dealt with many issues.  One of the things we discussed before the race was to never speak the word quit. It's also important to keep negativity out of the boat. When things aren't going well or you have an ache that is nagging keep it to yourself. Focus on your technique keep on top of your intake and most of those issues will sort themselves out.

I realize the original question is " what have you done to become more efficient?" So my answer is simple I have tried harder.
Rusty Coons
Boat 3737

Atollman wrote on 02/17/18 at 08:08:08:

A training run that is 30% of your projected finish time sounds like a great way to get burnt out, and is totally unnecessary.

Remember the phase " This sucks ! ". I think the mental part is the most important part of surviving and finishing the race.    You must be able to adapt to the current conditions .A clear mind and positive attitude goes along way.

A good practice run that doesn't require a lot of coordination is paddling upstream.  It gets you in the habit of paddling continuously and when you're done, turn around and head back to your ramp.

There aren't a lot of deep rivers around Des Moines so most of the initial practice getting comfortable in the boat was done in lakes.

The longest downstream practice we did last year was about 50 miles on the Raccoon River bumping over sandbars.

We made a point of trying a couple late runs to get more comfortable with night paddling and eating bugs.  Still didn't prep me for believing I was going to get eaten by a sand dredge at 2AM.

We used the runkeeper app to track distance and pace and river math to account for current and ETA.

I'm planning to do the SD kayak challenge for my big shakedown run this year.

The three body parts I'd worry about most are your arse, shoulders and stomach. 

1. Check your bum on the practice runs and add padding to the boat where needed.  Be careful that your padding doesn't add height and make you less stable.

2. Technique is more important than overall fitness for not burning your shoulders out.  Mine sucked for the first 2 days but got better as a I went.

3.  Go with food that works for you and try your nutrition out before race day.  For me it was trail mix, beef sticks, and Subway sandwiches.  Also be really careful with gels and drink mixes.  Not enough and you'll get depleted.  Too much and you'll shutdown your stomach.  Either way is a world of hurt and probable DNF.

Watch the videos on 340Paddler youtube channel.

Atollman, sorry to misread your post. Even a 30% run is really pushing the limits of a rookie. I think a lot of Vets could do it though I doubt many see the need.  I also have never had nutrition issues that early in the race.  There is something to be gained from a run that long if you are willing to do it though i'm sure.  I have had seat issues early on before I found what works for me.
Rusty Coons
Boat 3737

Rusty,
Your seat problem was resolved switching to a "Triebold"seat correct? Does that Savage River product exchange easily with a stock Wenonah bucket?
Thanks