Building your raft frame and getting a multi-day rig together can be like a frustrating game of Tetris. There are many measurements to keep track of, including what fits where and what size boxes you need.
Dry boxes come in a variety of widths and lengths, shimmed or unshimmed, and two or one-door options. You can also add a flip seat or captain’s chair to your frame, which changes what kind of dry box you need. Let’s take a look at how to choose a dry box, how shims work with a flip seat, and more.
How to Choose a Dry Box
There are three key measurements to be aware of when choosing a dry box:
- Length
- Width
- Depth
Unless you're building a custom box, manufacturer dimensions dictate exact sizes, and you have to decide which one works best for your frame.
Dry Box Length:
The length of the dry box depends on the distance between the tubes on your raft. Take this measurement from the apex of one tube to the other, not at the floor or from the top of the raft. Then subtract one inch from either side or two inches from the total length. For example, if there is a 40-inch wide profile on the inside of your raft, you will need a 38-inch long dry box.
Here’s a simple equation for choosing the right length:
Distance between tubes - 2 inches = Dry box length
Width
Most dry box manufacturers make boxes in a variety of widths, often in two-inch increments. For instance, Rio Craft offers boxes as wide as 44 inches, all the way down to 26-inch-wide boxes.
To find the correct width, measure the inside width of your frame bay where the box will sit. Then subtract ½ –1 inch from the total to ensure the box slides in and out easily.
If you have an adjustable frame, getting the bay dialed to a specific dry box width is a lot easier. If you have a welded frame, you have less flexibility and may need a custom box.
Depth
The most important thing for box depth (Or height) is keeping it off the floor of your raft. For this dimension, measure from the floor raft to the bottom of the frame bar, then subtract ½ –1 inches.
Height preference also depends on whether your dry box doubles as a captain’s seat or not. If your dry box is your rower’s seat or if you’ll be adding a flip seat over the box. Heights range between twelve and eighteen inches in two-inch increments.
Flip Seats
Using a flip seat over your captain's box is a great option for adding comfort to your rig. There are a few different types of flip seats. For both mesh-backed and the tractor seat versions, make sure the seat is an inch and a half wider than the profile of your box. For example, if your box is 16 inches wide, you would need a 17.5-inch flip seat.
Flip seats sit over the dry box and are supported by both cross bars. (The same cross bars that the dry box sits on.) Because the seat is wider than the box, it requires an extra ¾ inch on either side of the box. This extra space ensures the seat functions properly and won’t hit the edge of the box when you flip it down.
Dry Box Shims
This is where shims come in. Dry box shims are ¾-inch spacers that sit under the hang tabs and between the dry box and the cross bar. This creates a gap that allows the flip seat to clear. Most manufacturers make either shimmed or unshimmed boxes with the space under the hang tabs either empty or featuring a welded-in spacer.
It can be hard to know if you will eventually want a flip seat or not, or if other rowers using the boat will prefer a flip seat. This can make it even more difficult to decide which box to purchase. If you get an unshimmed box and later decide to use a flip seat, you can take the box to an aluminum welder and add shims. However, this is expensive and can warp the box.
Dry Box Shim Kits
In partnership with Rio Craft, 4Corners Riversports created a Dry Box Shim Kit. The kit includes four ¾-inch spacers that screw into the box’s hang tabs. This innovation allows you to add shims after the fact, and use a flip seat or not, with the same box.
The added 3/4" of space between the box and the frame allows clearance for a flip seat. (You will need to increase your bay width approx 1.5" with this shim kit, which only works on Rio Craft dry boxes.
Final Thoughts
Putting together your multi-day rig can be a long process, but when everything comes together, it is one of the most rewarding feelings. The dry box is an important element of any raft setup, and choosing the right size is essential. Check out our latest YouTube video or give us a call - 970-259-3893 - for more information about dry boxes, flip seats, and shims.
