Planking 101

Plank work Glacier Park Boats

 Words and photos by Tyrel Johnson:

As we venture into another season on the lakes of Glacier National Park, our crew makes their way into each location anticipating what surprises old man winter has left for them. Our docks, boathouses and boats all brave the long winter season differently. The docks fight the ice and the harsh wave action. The boathouses stand strong against the wind and snow loads. The boats, on the other hand, fight more of an internal battle. Their struggle toes the line between drying out too much or too little. If they dry out too much the planks shrink and seams open up causing the boat to leak more. Yet, if they do not properly breathe and they retain too much moisture another little beast by the name of rot can reek havoc.

Lake Josephine Boathouse


Three of our boats- Little Chief, Sinopah and DeSmet are over 85 years old!  Our boats have a long History in Glacier National Park… 



Water, with little air movement naturally provides a haven for rot to thrive. We ventilate the boathouses to provide airflow through and around the boats during the long fall and winter months in Northwest Montana. Inevitably, various parts of the boat need to be replaced in time. The nice thing about wooden boats is that you replace individual pieces as they grow weary.




The hull, the planks in which provide the exterior shape of the boat and keep the water out, require the most work. Around the water line, the wet/dry zone is the most susceptible to rot, therefore these planks have a shorter working life.


Morning Eagle

Our crew inspects the boats post and pre-season, and things definitely change over the winter. We have a list of the known items going into the park in the spring, but the unknown is always the kicker. The inspector “sounds” the hull, using a mallet to tap the hull listening to sounds the plank produces. If it sounds solid and reverberates the impact, all is well. If a tap sounds hollow or produces little bang with the blow, this is a suspect area.


If a further inspection of a suspect area results in a soft spot, a bad seam or a bad end of a plank (rot particularly likes to travel into the end grain of planks), we will pull the plank out. In order to pull a plank, we remove all fasteners, which are usually Silica-bronze screws. The original planks were installed with square cut galvanized nails. The nails need to be essentially chiseled out to reveal the heads, hit hard with a hammer to “set” them and then pulled with a cat’s paw (a type of pry bar). This takes time, and these planks are generally long to today’s standards, up to 24’ long!


Removing Old Planks



Once the planks are pulled, the oak frames and anything else visible through the plank opening are inspected. If the inspection results in additional rotten components inside the boat, it is another situation entirely because access is sometimes nearly impossible.

Planking Glacier Park Boat Company


Various measurements are taken to determine the size of the board needed to replace it. These knot free western red cedar boards are sometimes up to 18” wide and 18’ long. Eventually, this board will be surface planed to thickness, marked to match the shape of the opening in the boat and cut into a curved shape to be transformed from a two-dimensional board to a plank on a three-dimensional boat.


So, as the leaves flourish and spring warms the water on the west side at Lake McDonald, we get the DeSmet all wrapped up, launched and running tours. Then crew heads off to do it again at Two Medicine, Many Glacier and Rising Sun. Crossing our fingers as we listen to what the boats have to say. We look at the boathouses and docks to see what the driving forces of nature have accomplished in our absence. We rally our troops until the boats, boathouses, ticket offices, houses and docks are all ready for the season, keeping them solid year after year, plank after plank.