This article is part of our Rising Star Portfolios series.

On Dec. 2, 2007, just before 6 a.m., I treaded water in the Indian Ocean off the western coast of Australia. The water was crystal clear; the vista serene, even peaceful.

Boom! A gun went off, and 1,000 finely tuned athletes -- specimens of human physiology -- churned the sea a murky gray.

Thus began Ironman Western Australia, a triathlon including a 2.4-mile swim, a 112-mile bike ride, and a 26.2-mile run under the scorching Australian sun. After months of grueling training -- and years before that just to be fit enough to handle the training -- I was in peak form. I'd raced shorter triathlons for years, but this was my first Ironman, and I had every intention of absolutely crushing it.

Physical preparation for an Ironman is crucial, but ultimately it's a mental undertaking. You need to make your mental plans -- pacing, nutrition -- before race day. You want to minimize decisions to be made under the stress of racing. One maxim you absorb is patience: It's a long race, and you need to be conservative early to avoid disasters later.

It was in this context that, about 15 minutes into my first Ironman, I noticed a troubling development. In the frenzied swim start, the front of the field had split into two main packs, and I was in the second one. The gap to the lead group was already about 70 meters -- and growing.

I faced a choice. Stay put and safe, but risk never seeing the race leaders again -- or gamble and try to close the gap, but risk blowing up and ruining my race. I went for it. For a dozen heart-rate-jacked minutes, I dug deeply and slowly, slowly pulled back to the leaders. I settled back in, and a fantastic bike ride and a strong marathon later, I posted a great first Ironman performance.

In my Young Gun Portfolio, I approach investing much as I approach triathlon, keeping three particular mantras in mind.

1. Endurance is vital, but you need to know when to make your move.
Make no mistake: The Young Gun Portfolio is a long-term portfolio. But that doesn't mean we're sleepy. Just as knowing when to go for it is critical in triathlon, knowing when -- and being able -- to make opportunistic moves is core to the Young Gun philosophy. It doesn't get much more opportunistic than our investment in Pebblebrook Hotel Trust (NYSE: PEB), in which we have a jockey investor buying up debt-heavy hotels for us on the cheap. In November, this stock was trading for just book value, and we struck when the iron was hot.

2. When you commit, fully commit.
What would have happened if, while trying to catch the lead swimmers, I had continuously reevaluated my decision? I'd have been distracted, unfocused, and, as my oxygen deficit grew, double-guessing myself. Once you make an investment decision, stand by it. Besides forcing you to be more careful in your decisions, this also gives your decision time to play out.

The Young Gun Portfolio's recent investment in banana master Chiquita Brands (NYSE: CQB) will undoubtedly face questions. Chiquita is nothing if not volatile -- tropical storms, euro exchange rates, banana prices, and fuel prices can all swing wildly. I've accounted for all these in my analysis and still think Chiquita is a good deal. But we can't run at the first wind of a Caribbean hurricane -- we need to stand strong and allow our thesis a chance to play out.

3. Prepare for contingencies.
I mentioned that I trained extensively for my first Ironman, but I didn't specify how. I trained with the express goal of preparing for any situation. I trained in the heat and the cold, calm waters and rough. I induced digestive problems so I could practice dealing with them. And yes -- I practiced surging during long swims in case I had to close a gap. So when the time came, I was prepared to make an aggressive decision.

I approach Young Gun investing the same way. We wait in the wings, analyzing opportunities, adding the best to our arsenal of potential investments. Then when the time is right, we make a move. I've mentioned U.S. dredging company Great Lakes Dredge & Dock (NYSE: GLDD) several times as a stock in my arsenal; if falling international revenue causes a steep price decline, you can bet we'll be in there in a flash, because our homework is already done.

Getting ripped
The Young Gun Portfolio is for young investors -- or the young at heart. Our returns can be volatile, but over the long term, our approach should yield superior results for those who can stay the course. If you think you have what it takes to be a Young Gun, follow me and the portfolio here.

This article is part of our Rising Star Portfolios series, where we give some of our most promising stock analysts cold, hard cash to manage on the Fool's behalf. We'd like you to track our performance and benefit from these real-money, real-time free stock picks. See all of our Rising Star analysts (and their portfolios).

Alex Pape owns shares of Pebblebrook. The Fool owns shares of Pebblebrook Hotel Trust and Chiquita Brands. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.