Introduction: Wooden Floor for a Seahawk 4 Fishing Raft

About: I work in industrial automation and spend any free time making.

Apartment life has its perks, weekends free from yard work and unexpected home repairs, But one thing most apartments lack is storage space for fun weekend things like canoes. Kayaks are small but not very 4 year old friendly.
This is how I was introduced to world of inflatable boats. I was hesitant at first but ultimately after being realistic about what we would be doing in the craft, lake exploring / lazy river floating and fishing for $100 what did I have to lose.

Step 1: Getting to Know the Seahawk 4

Once getting the raft home and inflating it I was impressed by the thickness of the 30 gauge PVC sidewalls of this thing. I would not want to hit class 3 rapids in it but it did not feel like a pool toy either. I was also taken by the size of this raft the dimensions on the box nearly 12ft long and just under 5 ft wide. Be sure to use the inflation gauge that comes with the raft it is easy to over inflate this is a common cause of issues in inflatable boats.
On the water with 2 adults and 1 child the raft was quite stable but as would be expected it doesn't track or paddle like a hard body boat. But this raft can float in less than 1ft of water and is quite manuverable.

After the fun filled maiden voyage I had three things to improve on: The oars that come with the boat are bit short and I plan to replace these. I have an idea to use the rafts motor mount lugs to attach a skag to help with tracking. The final area and first project was installing a wooden floor for better stability.

Even though the floor mod is a popular one for this raft I had a hard time finding any good construction info or details.

Step 2: Inflate, Measure, Cut

After fully inflating the 3 chambers of the raft measurements were taken of the underside of the floor chamber. I am not posting every test fit and trim etc the dimension pic above is the final used dimensions after test fitting. If you spit the floor into 3 sections as i did to minimize storage space remove 2 inches from the center panel length. If you are making a 1 piece floor the measurements shown should work fine.
I used 3/8 plywood sheet this was ok but I feel 1/2 would have been a better choice after testing on the water.

Step 3: Sand Edges and Trim

After getting the floor cut sand the edges to prevent splintering. I used 1/2 foam pipe insulation (the kind you can find at any hardware store for $0.99 a stick) to pad the edges. Drill a parameter of holes 1" inside of the outside edge of the panel. The holes should be placed about 6" apart for cord or wire ties to lash the insulation to the edges.
I've seen staples used for this but pointy objects and inflatable things don't get along. Plus after use the foam will pull through the staples and have to be reattached.

Be sure to do a test fit with the edge covering before carpet covering. Also be sure to add a hole in the rear to access the floor chamber filling valve.

Step 4: Cover With Outdoor or Auto Grade Carpet

I covered both sides of my floor panels with automotive carpet. It can usually be found in 6ft x 8ft pieces and this was perfect for project.

The basic idea is to lap the bottom side of the carpet over the edges and staple on the top side of the panel then the top cover is cut to the edges and stapled over the overlap. This will ensure all staples are on the top surface. If they start to back out you can see this right away in stead of being hidden underneath. I kept all staples as close to the board edge as possible so that the once the pipe edging was attached it too would cover / protect the boat from loose staples.

Step 5: Test Fit and Finish Up

If creating a sectional floor Completely cover and trim the bow and stern sections. Place these in the raft and test for the center section. This is when I realized the center would need ~2" taken from the length. Once all is fit correctly cover and trim the center section and enjoy your new robust floor.

Step 6: Final Notes

The biggest plus to this project is the cost to fun ratio. I had to purchase all the materials for the floor upgrade which was around $35. Altogether including the cost of the raft I spent less than $150 for a portable rec. boat.

One could go all out adding seats and decks but then you would be in hard side boat money or you could buy a professional grade pack raft that will be rated for extreme rapids and made of ballistic material.