Sea Eagle Explorer 380x Flatwater Skeg

A flat water skeg replacement for a Sea Eagle 340x / 380x / 420x Inflatable Kayak.

I have a pre-2012 Sea Eagle 380x that I picked up second hand that I take out flat water kayaking. Sea Eagle used a drag behind skeg design and originally sold this on Amazon as ASIN B000SL3ULM. However my kayak did not have this and Sea Eagle no longer sells this part, so 3D Printing to the rescue!

With the assistance of Copilot I was able to design two versions of this skeg that mimic the original part.

Rather than attempting to redesign the bolt and nut I remixed the excellent T-Bolt Metric Set by PhilA (referenced in the remix notes). I used the M10 Bolt and Nut however they were not long enough and the original author did not provide a parametric (OpenSCAD) model to make the bolt longer. Rather I simply used Orca Slicer to scale along the Y Axis 175% of both the Bolt and the Nut which worked out excellent. I cannot express how much that design of the Bolt and Nut are very slick and smooth, printed in PLA. I have uploaded STL's of the ones I used here.

Versions

1. skeg.scad (skeg-460.stl / skeg-460-HoleAndPeg.3mf / skeg-460-DoveTail.3mf)

   1. This is the version of the skeg I ended up going with, it is exactly 9mm thick as this seemed to be the maximum width of the mount on my Sea Eagle 380x.

   2. I personally went with a 460mm long version as this is what Copilot recommended and using this I felt confident in its assessment. A raw STL of this length is included.

   3. However this is far too large for either of my printers (FlashForge AD5X and FlashForge AD5M Pro) therefore I ended up splitting the model into two parts. Originally I went with a hole and peg join. However I was worried that this design would not hold up so I did an alternative cut that used a dove tail design. In both cases I used super glue to join the two pieces together and along the seam.

2. skeg-bulge.scad (skeg-bulge-460.stl)

   1. Still worried that my design would not be strong enough I started down a path of having Copilot create me a "bulge" in the center of the skeg of a configurable thickness (the connector piece must be 9mm in order to fit) to provide more material to have this grip on to. However I did not fully pursue this path as I ran out of time prior to my trip. This is provided in case someone wants to make a run at it.

Print Materials / Settings

• Originally I printed this in PLA but then also printed it in ASA, as you'll read in my review the PLA seemed to hold up fine. Both were Flash Forge Branded Black PLA, if I were to do it over again I would print them in bright orange.

• 3 Wall Loops / 50% Infill / Gyroid Pattern - I was worried about strength of the skeg so went with these settings for both the PLA print and ASA print.

• I printed both the Hole and Peg as well as the Dove Tail models, in both cases I used excessive amounts of super glue to glue the two parts together.

Review

Ultimately I ended up taking two Skegs, two bolts, and 3 nuts on a 3 day river trip down the Missouri Breaks from Coal Banks Landing, Montana to Judith Landing, Montana (approximately 50 river miles).

I decided to start the trip with the PLA printed Hole and Peg model with low expectations around durability, keeping the ASA printed Dove Tail in reserve.

Disaster struck early in the trip when at the boat ramp to put in the nut slipped from my hand and landed in the water. Somehow, miraculously, I was able to grab the nut before it floated too far down the river. Lesson 1 is to keep the backups out of your dry bag and ready to roll, Lesson 2 would be to print these in bright orange rather than the black they were printed in. I got lucky here.

Surprisingly this PLA printed Hole and Peg version lasted the entire trip, this despite running aground in rocks on day 1 and day 3 and mishandling on day 2 after pulling the boat out of the water at the second camp wherein the skeg was placed in such a way that the entire weight of the kayak was set atop of the skeg.

This thing helped my kayak track straight as an arrow even though some high winds on the water.

I did not see excessive wear, nor any major sun damage despite being in the water for approximately 8 hours a day for 3 days and left in full sun for the PLA.

The bolt and nut performed excellent as well, with no loss of tightness on the bolt (a concern and hence why 3 nuts were taken with only 2 bolts) a further improvement might be some type of hole in the bolt to allow a hold pin to be placed, but again seemed unnecessary.

However I still felt strongly about having the spares onboard the boat just in case.

I hope this model is useful for someone else; see you out there on the river!