Standing on rocks below a broken dam on the Salmon River in Colchester last week, my son Tom and I stared at a torrent of water that thundered through a narrow gap, cascaded several feet down ledges, and then reared up into standing waves surrounding giant, partially submerged boulders.

“Gotta stay right, but not TOO far right,” I shouted.

Tom nodded.

“Then go left and head for the first hydraulic. Punch right through it,” he replied. Most important, Tom stressed, “Keep paddling, maintain your momentum.”

He who hesitated would be lost – or at least flipped over into tumultuous water.

Tom and I were scouting the route we would follow soon in kayaks – an adventure that can only be done in high water, usually in early spring. When the river level drops, jagged rocks at the breach protrude, making a kayak plunge more perilous, if not impossible.

Tom and I have been shooting the dam for years, and every time has been slightly different. Last year we hit it at near-flood level, which in many ways made the ride easier, since the force of the water did most of the work. All we had to do was keep our bows straight and focus on staying upright.

Last week, though, the river was considerably lower – in fact, slightly below the recommended paddling level listed on americanwhitewater.org, which relies on flow gauges to report on river conditions throughout the United States.

This is why Tom and I spent extra time scouting the breach from upstream and downstream spots. We also decided to skip most of the northern section of the river, because low water would make the voyage too “bony.”

In past years, we’ve launched about three miles upstream on River Road and paddled through Class I and Class II rapids before running the dam, a solid Class III. Class VI would be Niagara Falls.

Upon arriving at the river, we drove past the covered bridge on Comstock Bridge Road, just north of Route 16, and pulled over to check out the dam in half a mile. We then continued right onto unpaved River Road for another mile and a half. Anglers had parked all along the road – the Salmon is one of the state’s prime catch-and-release fly-fishing destinations.

We pulled into a parking spot near a man who was fiddling with tackle, about to head down a bank to the river. Turns out it was an old acquaintance, Gordon Gruetzmacher of Groton, former race director of the Pfizer triathlon.

Sometimes there are conflicts between fishermen and kayakers – anglers upset that paddlers scare fish, and kayakers complain that fishing lines get in their way – but Gordon scoffed. The river is plenty big enough for everyone, he said, promising not to hook us when we paddled past.

We wound up driving a little farther to a better launch site, lugged our short, plastic whitewater boats to the water, and shoved off.

The river was indeed bony, and we repeatedly bounced off rocks while weaving through gentle whitewater. Worst were the “smoothies,” rocks just below the surface that look like calm water. A couple times I spun around backwards after striking these hidden obstacles, but managed to straighten out in time for the next set of rapids. Every so often we pulled behind giant boulders into eddies of calm water, to assess our progress.

“I’m glad we didn’t start farther north,” I said. There, a greater risk would be “strainers,” trees that fall across the river and snag unwary paddlers.

In a short distance, we spotted Gordon, standing mid-river in waders. He lifted his rod to give us more room, and I gave him a thumbs-up as we swept past.

Tom and I heard the waterfall roar long before we saw the broken dam, which once was part of an old mill.

“Do you want to get out and take another look?” Tom asked.

I shook my head.

“Let’s do it.”

Tom, who long ago surpassed his old man as the superior paddler, would go first, then pull ashore and wait for me.

I clung to a log 100 yards upriver and watched him weave around a couple rocks, pick up speed and then – whoosh! – disappear down the drop. A moment later, I could see him steer for shore, where he got out of his boat and scrambled onto a wall overlooking the old dam.

I took a deep breath, tightened my spray skirt, adjusted my helmet, and let go of the log.

The current soon gripped me. No turning back. Ahead, swirling froth and foam exploded through the breach.

Stay right, stay right, stay right, I told myself – but not TOO far right.

Fifty yards, 20 yards, 10 yards … then, in a heartbeat, the torrent sucked me through, sweeping past a blur of boulders on both sides.

A flash reminder: Head for the standing waves! Head for the standing waves! I swerved left, water sweeping over my bow, and plunged through the first haystack, then the second.

Dead ahead, another jumble of boulders loomed. I think Tom was trying to tell me to go left around them, but the shore beckoned closer to my right.

I executed a low brace, spun around, and paddled furiously upriver to my right, finishing the hard way, but at least still upright.

After stepping out onto terra firma, I finally exhaled.

“Mission accomplished!” I exclaimed.

“A great paddle,” Tom agreed.

We’re already thinking about next year.