Pontoon boat

12’ long x 5’ wide

Picture of completed boat
Picture of completed boat

Boats come in all sorts of shapes and sizes for many different purposes. In this case, the requirements for the needed boat are mainly to be small, lightweight, and simple to build. It is also necessary that this boat be able to carry multiple people around in shallow water, be pulled up on a beach, and work well in the Sarasota Bay weather. JEM Watercraft’s Pontoon boat design fulfills all of these requirements and works best for the main requirements.

The Pontoon boat is a simple multihull boat that can be assembled with plywood and lumber. Both hulls are 12 feet long and are connected by a thicker, unshaped 4’x8’ piece of plywood. This boat is meant to be taken out on calm waters, preferably when there is not much wind and, by association, smaller waves. Its design is easily to cut out and put together in a short amount of time, making it an easy-to-assemble day cruiser. It is also designed to be easy to make and assemble with a few amount of people. It uses 6 sheets of plywood to make both 12 ft. hulls, roughly 3 for each one. As the lines drawing below shows, each hull is made from a top, bottom, and two sides, with no transoms on either end. The measurements for each part of the hulls are not shown.

Pontoon lines

Lines Drawing (Nesting)

One of the main good points for this design is that the simplicity of its design makes it an easy boat to build. When building the boat, the symmetrical hulls and the lack of complicated parts makes it incredibly easy for a beginner boat-builder to cut out and assemble. Since both hulls are symmetrical, it is easier for the builder to keep track of where certain parts are supposed to go, as some parts are effectively interchangeable. Similarly, the lack of complex parts to assemble, such as a keel or rudder, make the boat parts easy to measure and cut out on the plywood available.

 free pontoon plans

Symmetrical hull shapes

Another benefit to the pontoon boat’s design is how it is easy to ride and handle in shallow waters. In the water, it would act as a floating platform and could float in only a couple of feet in water. This makes it easier for it to maneuver around without running aground, especially during low tide or on the Gulf Coast. In addition, the flat bottom of the boat makes it easy for the person using it to drag it ashore onto a beach and takes away the need for a trailer to pull the boat out of the water. For Sarasota Bay waters, this boat is easy to maneuver and would have the least amount of trouble with the shallow water around compared to most other boat designs. It would be easy for someone to use it in the conditions in which it would be used.

However, this simple design does come with some drawbacks to it. There are no built-in seats on board, so passengers would either have to bring their own foldable chairs or sit on the flat surface of the deck in order to sit down. Furthermore, only 3 people total would be able to comfortably fit on the boat at one time. While the boat can carry up to 800 pounds of weight, the dimensions of the boat’s deck are too small for many more people to fit on top. Another drawback of the deck is that it does not have any railing built into it. Railing would have to be built on top of the boat deck to keep people or objects from going overboard, which would lower the amount of weight that the boat could carry. Added with the weight of the electric motor that would be attached to the back of the boat (with a short transom added to the back of the boat’s platform), the Pontoon boat’s carrying capacity could be greatly decreased. The added weight would also make it harder for the boat to navigate in shallower waters. The Pontoon boat’s design is not entirely flawless, but it works well enough for its purposes.

 this is also the boat

Pontoon boat with attachments being taken out on the water

The Pontoon boat can be powered by a small electric motor, as seen in the picture above, or by rowing. It is lightweight enough to row in an emergency, but that and its structure makes it a terrible boat for enduring rough weather conditions. It’s a boat meant for cruising out on a calm day, with no accommodations for staying out on the water for more than a couple of hours. It’s a pretty, simple boat, and is designed to cruise around the ocean shore or a calm lake, not going far off from land.  It doesn’t have much power, but just enough to get around places where it needs to go.

The materials needed to build it and the cost of them are as follows (with the list of materials according to the Bill of Materials):


MATERIALS*:4×8 plywood

  • 6 sheets ¼”
  • 1 sheet ½”

12 ft. 2×4 lumber


3.6 gallons epoxy resin


65 yards fiberglass tape (9 ounce, 4”)


2.3 quarts wood flour





*does not include tools, safety equipment, etc.

COST:$15.50 * 6 (RevolutionPly) ($93.00)

$5.47 (Top Choice)

$34.07 * 6 (West System 105A) ($204.42)
$16.34 * 6 (West System 205A) ($98.04)

$38.00 * 1.3 ($49.40)


$10.99 (1 q) * 2.3 ($25.27)


Subtotal: $503.87

Taxes:     $  35.27*

TOTAL:    $539.14

*taxes assumed to be 7%


With the added cost of an electric motor to power the boat and other small materials needed, the total cost of materials comes out to be more like $860 (including taxes).

A rough order of construction would be as follows:

  1. Measure and draw out lines on 6 sheets of ¼” plywood
  2. Cut out shapes and sand off any edges
  3. Butt block two halves of one floor panel together and bevel the edges of the block
  4. Stitch together the bottom and side panels
  5. Stitch the bulkheads to the bottom and side panels. Make sure everything is lined up properly.
  6. Tape the outer seams of the pontoon together with masking tape and coat wood around seams with epoxy
  7. Tack-weld the bulkheads and panels into place
  8. Remove stitches
  9. Fillet and apply fiberglass tape to seams. Spread excess resin all over interior wood. Make sure wood is covered in 2 layers of epoxy.
  10.  Cut strips to form Tcleats and glue then into place.
  11.  Flip hull over and sand the outside seams down
  12.  Fillet any holes or seams. Apply fiberglass tape and epoxy to the seams. Make sure outside hull is coated with 2 layers of epoxy.
  13.  Flip hull again and coat any bare wood with epoxy
  14.  Apply glue material to top of Tcleats made earlier and place top panels down to push contact onto all of the Tcleats.
  15.  Fillet seams and apply fiberglass and epoxy to them.
  16.  Repeat steps 3-15 for other hull
  17.  Align hulls parallel to each other
  18.  Cut 3 4’ long 2×4 beams for each hull
  19.  Glue lumber into place, aligning pieces with each other on respective hulls to form a frame for the plywood deck.
  20.  Fillet and tape seams around lumber and coat bare wood in epoxy
  21.  Glue plywood deck to the beams and fillet and fiberglass seams
  22.  Coat deck wood in 2 layers of epoxy
  23.  Add any modifications and attachments
  24.  Sand, fair, and paint


Source for plans: “Free pontoon boat plans,” JEM Watercraft, JEM Watercraft, 2011. Web. http://www.jemwatercraft.com/pontoon.php

2 thoughts on “Pontoon boat”

  1. looks really good with graphics and layout. consumables is always a good line item for materials – they usually come out at 10-20% of cost. good writeup

  2. Hi, a good analysis of the basics for this craft… thoughtful and balanced. I’d like to get in contact with you about a pontoon boat project we are undertaking here in Thailand. I intend to use these plans as a base with a few additions that achieve our build objectives. This project might be of interest to you also? Kind regards, Dr Douglas Wilde-Amnat Charoen, Thailand. 19/12/14.

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