I wanted to update my blog to let folks know that I had performance issues with my flat bottom designed boat. I believe I caused the issue by adding so much weight forward in the cabin and pilot house. The boat had a real control issue. It would not steer well at low speeds. The boat would just seem to slide sideways instead of turning. In reverse there was no control at all. The front of the boat would fish tail back and forth banging the dock on the way out of the ramp.
I contacted the hull designer, Jeff Spira of Spira International Inc., and discussed the issue with him. He recommended that I add a strake down the center on the hull bottom. He suggested a 1×4 – 6 feet long mounted on it’s edge, starting at the transom running forward 6 feet. After discussions with him on how to mount the strake (I call it a Keel) we decided on a 2×4 – 6 feet long on it’s edge, and due to possible cavitation with the motor it was moved forward starting 3 feet from the transom.
I discussed how to mount the piece with Jeff and with several other folks. I was first looking at a piece of white oak for the job, planning on epoxying it to the bottom and fiber-glassing it for durability. Jeff told me he would not epoxy or Fiberglass the piece. He said that I would be changing it from time to time due to wear.
It was recommended by the Dealer at my local Yamaha store that I use a structural plastic 2×4 for this job. I found one available locally, I purchased it and made my “keel”. The front is rounded and the aft end is tapered back to 1”.
I then installed it to the bottom of the boat using Stainless steel #14×5” structural screws that I ordered online. I put a screw every 8” down the length of the Keel, sealed it to the bottom with 3M 5200 adhesive sealant.
I took the boat out today and it performed great. Backing out of the ramp was perfectly straight. Turning at slow speed works great now and turning at higher speed is much improved. The difference is like night and day. I actually felt like I was in control of the boat today.
Here is a video of the performance testing. The boat is riding a little high and I plan to work on that. If I get it fixed I will update the blog. https://www.youtube.com/watch?v=Ps0k3Zuzds0
Thanks for looking!!
-- John, Suffolk Virgina