Modular Test Bed

Modular Test Bed

I am almost ready to make my next boat.  Almost.   Honestly, I simply can’t believe how much this choice has been vexing me.  I’ve been pondering the question for at least a decade, and seriously so over the past two years.  In that time, I’ve changed my mind… constantly.


This could be my last boat.  Chose well.  Ack!  And… for the past decade I worked for a nightmare of a boss.  I dreamed of escape.  Often I dreamed of crossing the Atlantic Ocean in some crazy small craft. Other times I dreamed of boat trips across the waterways of the country, trips that would take months.  Escape.

Now I am retired.  I have nothing to escape from.   So… what do I want?  Well, I’ll share more about that soon.  In the meantime, I do a small build for fun, one that could serve as a dinghy, of sorts, for whatever big boat I build next.

I’m designing and building a modular pontoon.   Build a dozen or more sections and put it together in any way I chose.

Here’s my first configuration:

Numbers for each pontoon:

  1. 3 feet long – length of each pontoon
  2. 7.75 inches wide and deep (dimensions of each side of a pontoon.)
  3. But first, calculate with the pontoon only 4 inches deep.

Here’s the math:


  1. One full pontoon = 41 pounds of flotation each.
  2. One-half pontoon (end pontoon) = 20 pounds
  3. One front and one back pontoon = 40 pounds
  4. One center and two end pontoons = 81 pounds.  Multiply by two assuming a raft with two pontoons. = 162 pounds flotation.

So… to float 280 pounds – me plus a bunch of “stuff”

Two pontoons

  1. 4 end pontoons = 80
  2. 6 center pontoons = 240 pounds – 3 on each side
  3. 8 pontoons at 3 feet long each = two pontoons at 24 feet long


Three pontoons

  1. 6 end pontoons = 120 pounds
  2. 6 center pontoons = 240 – two on each of three pontoons
  3. 12 pontoons = 360 pounds buoyancy – 3 pontoons with 4 each is 12 feet long.
  4. Possible width – assume each pontoon is 8 inches wide. With 8 inches between each.   24 inches of pontoon plus 16 = 40 inches wide

Or, assume 5-inch submersion of each pontoon. Much better results.

So… to float 280 pounds – me plus a bunch of “stuff”

Two pontoons

  1. 4 end pontoons = 100 – 25 pound each.
  2. 4 center pontoons = 204 pounds – 2 on each side
  3. 4 pontoons at 3 feet long each = two pontoons at 12 feet long

304 pounds buoyancy.

This clearly works better.  Note that I haven’t figured in the weight of the boat itself, but there is plenty of buoyancy left in the calculations.

More details coming.

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