So I will start with experimenting with homemade sponsons exactly in folbots
dimensions. Then I can switch to the commercial product if mine are not reliable.
That is a good approach. Also consider having the PVC welded . A Sonnet 17.5
builder in Scotland has taken this approach and has achieved excellent results.
Do you have any advice not mentioned on your (excellent and helpful) website
when building sponsons?
Commercial sponsons that are the correct size are available for the Sonnet 14 and
Sonnet 16 at a reasonable price from Folbot. I recommend that you purchase them.
For the Sonnet 17.5 and Sonnet Double homebuilt sponsons are required... Welding
is recommended vs gluing.
Blunt sponson ends like Folbot's should come to within about 6" of the aluminum stem
tubes. The length of the upper and lower sponsons will determine the slope of the
stems. Homebuilt tapered sponson ends can get even closer to the stems.
Glued 17' X 4.75" Sonnet Double sponson pics and details are seen below.
Circumference = diameter X 3.14 (pi) .... 4.75" X 3.14"( π) = 14.9".
You must also add for the overlap or lip.
Glued Overlap Seam with PVC elbows ( Right Angle Flange) ...Blunt ends ( non tapered)
Glued Lip Seam with tapered ends