Floors

The term “floor” when used in describing a wooden boat does not refer to what you might walk on—that would be the cockpit sole or cabin sole (or in Justine’s case, the cuddy sole). Rather, a floor is a key component of the boat’s backbone that serves to tie the boat’s frames into the keel.

Justine has a floor and two frames at each station where there’s a construction mold. Except amidships, in the way of the centerboard trunk, each floor spans the frames where they are almost touching at their connection to the keel (which is high up on the construction molds while the boat is being built).

The floors are all triangular but their sizes vary considerably from station to station. Far forward, the hull has a steep “V” shape, while amidships the angle is much shallower. In addition, the depths of the floors vary considerably. Many of the floors support the cuddy sole or the cockpit sole, and three of them support bulkheads. All of these details are given on the plans.

Justine’s floors are all made from live oak planks. They vary in thickness from 7/8″ to 1 3/8″.

The floor at station 12 is one of the largest, and its top edge is rabbeted to receive the bulkhead between the cockpit and the cuddy. The floor at station 2 is the smallest, and here it’s sitting on top of station 12’s floor.
Fitting a floor

The next series of photos shows how I made a fitted the floor at station 3.

Construction mold 3 ready for fitting its floor. Temporary cleats allow the frames to be tightly clamped against the mold, and a cleat has been added at the correct height for what will be the top edge of the floor. I used a block plane to make a “flat” near the top of each frame so that the frames would fit snugly against the floor.
A blank for the floor is clamped in place on the mold and marked for trimming to size. The cut will be bevelled to match the angle of the frames.
Making the bevelled cut on the band saw.
Each floor will be bolted through Justine’s keel plank. It’s easiest to drill these holes at the workbench, before riveting the floor to the frames.
Each frame is attached to the floor at station 3 with three copper rivets. The beveled cuts on the floor were left slightly oversize so they could be planed to match the frame bevels once the floor was riveted in place.
Riveting

Quite a few of the fastenings in Justine are rivets made from copper nails. The plans indicate where rivets should be used, and what size nail to use. Rivets are used in locations that are not likely to ever need tightening or replacement.  The tools I used for riveting are shown below.

Materials and tools for riveting. Clockwise from left: Copper nail, copper burr, burr setter, bucking iron, diagonal cutters, ball-peen hammer.
A hole that closely fits the copper nail is drilled through the frame and floor. The nail is driven from the frame side, then a copper burr is set over the nail’s point and driven down against the floor using the burr setter.
The pointed end of the nail is cut off using diagonal cutters. The cut preserves a length of nail beyond the burr so the rivet can be headed over the burr. A length of about 1.5 times the nail diameter is left for forming the rivet head.

The part of the nail that protrudes beyond the burr is struck repeatedly with a ball-peen hammer and this flattens and rounds over the end of the nail, forming the rivet head.

The bucking iron is placed firmly against the nail’s head, then rapid light taps with the ball-peen hammer are used to “upset” the nail and form a rivet head that fits tightly against the burr and overlaps it.
Limbers

My father-in-law Sandy once questioned my desire to build wooden boats by telling me: “Wooden boats leak.” That didn’t deter me. Rain water also can get into a boat (even one made of fiberglass!). To deal with the inevitable accumulation of water, the hull must allow for draining any water that accumulates to the lowest point of the hull, where it can be pumped out as necessary.

Because of their placement in contact with the keel plank, floors are barriers to fore-and-aft flow of water in the hull. “Limbers” are passageways that allow water to move past each floor and thereby collect at the lowest point in the hull, in Justine’s case between stations 12 and 13, beneath the forward end of the cockpit sole.

Floor at station 12. A 1″ hole has been bored to allow water to move aft to the low point of the hull. There are two keel bolts at this station, positioned symmetrically about the limber. The frames at each station are trimmed to match the bevel at the base of the floor, as seen here.
Midship floors

The centerboard trunk intersects the floors from station  13 to station 17, so the floors are altered to accommodate it. Keel bolts will pass through the keel plank, bedlogs, and floors at these stations, and limbers are placed outboard of the bedlogs.

From stations 13-17 the floors need to accommodate the centerboard trunk. At station 13 only the forward tip of the trunk intersects the floor and the floor extends from port to starboard. The trunk is much deeper at stations 14-17, so at each of these stations there is a starboard floor and a port floor. Limbers will be cut in floors and frames adjacent to the centerboard trunk bedlogs. (The floor at station 14 is aft of the construction mold, a detail shown in the plans.)

I made and installed Justine’s floors between August and November 2009.

With the frames and floors in place we’re ready to make Justine’s stem and transom and add them to the backbone structure.