Thank you for visiting our Ship Ahoy Exhibit.
Why use trunnels and not use nails in building wooden ships?
Answer:
On vessels that were designed for the mercantile trade, the hull planks were at least 2 inches thick, and up to 6 inches in thickness. In the period before the late 1800s, iron nails sufficient for such thick planking were fairly expensive and not generally available.
Further, trunnels were less prone to corrosion and splitting, which could weaken the ship’s hull. While metal fasteners like iron bolts offered mechanical strength, metal nails could also corrode, especially in saltwater, and accelerated wood decay around the metal cause or “nail-sickness.”
Trunnels, being made of wood, would swell, allowing them to grip tighter in the wood and maintain a secure hold over time.
What Really Kept the Water Out?
Answer:
Keeping the water out of a traditionally built ship was an ongoing challenge. That is why vessels needed to have a bilge pump.
First, the seams between wood planks were caulked with oakum, which was often soaked in tar or pitch. This sealed the gaps between the planks.
Second, the planks swelled in water. A plank could swell ⅛ to ½”. This natural
swelling helped to close the gaps between planks, making the hull tighter. When ships
were launched they had to “take up” for a period of time, allowing the planks to swell,
before it was safe for them to go to sea.
Finally, the seams were filled with tar or pitch.
Where Does “Knox” in Knox Engine Come From?
Answer:
The Knox engines were manufactured by the Camden Anchor-Rockland Machine Company, based in Camden and Rockland, Maine. Both both towns are in Knox County.