Slightly Unconventional Footy

There have beeen several threads on this site regarding the prevention of submarining while running. I am now developing an idea that uses an unconventional method. It is an extreme version of Flavio’s large jib, mounted on a long bowsprit, but with no mainsail. The jib should provide lift when running, reducing the downward force on the bow. The elimination of the mainsail also reduces submarining forces. But the lack of a main requires moving the keel far forward, all the way to the bow. But the bulb weight needs to be below the center of the hull, so a very long bulb is needed, to extend back from the keel. A proof-of principal model was built, to see if such a monstrosity would actually sail (it does). I was visiting my grandchildren in Indiana at the time, and had no access to tools or materials, so the boat is just a free-sailing section of a foam swimming noodle (no radio control). It does actually sail, and the obviously fragile bulb-to-keel attachment has survived a few weeks of abuse. A more controllable version will now be built, to see if there is truly any advantage, and to answer a whole bucket full of obvious questions.

I tried something like that out on a full size Sprog. It didn’t work out to well. Strong gusts still caused the bow to go under. But I hope you get the bugs worked out becuase I would love to have a rig that wont pull the model under.

I think you will get a call from somone named Andrew or Andy… :slight_smile:

Why do I suspect that boat would sail better backwards?

(If you slid the rig toward the middle of the hull and sail it rudder forward.)

Hi its AndyT poking his periscope up for a quick look.

I radically looked at the hull sections and as part of a vac-forming excercise took a Vortrekka hull and converted it into FootyCAT

The shape of the cross-sectional twin hulls allows FootyCAT to not only increase buoyancy as pressure is increased and water is allowed to flow directly off the deck - the resultant effect is that FootyCat presents a very stable platform for various sail plans.

Her generous rocker up to the bow allows uplift in a skiff like manner and as such it is only when she is hard pressed and close hauled with only one hull in the water does she even start to take water over the bow and as she does so buoyancy increases so negating the effect and all of this without bow foils to help increase the lift!

Apparently there is nothing new under the sun. I noticed that in the Mariner thread that Neil had already tried something very similar to my “slightly unconventional” design. I have perhaps taken it a step further by moving the sail as far forward as possible, to get the tail of the thrust vector (when running) as close as possible to the pitch axis. I have not yet taken it any further than the first posting in this thread, due to frequent traveling. But some initial testing has indicated that it might not be as effective in reducing submarining as I had hoped. Other comments on this thread are also not very optimistic. Meanwhile most of my efforts are on completing the Origami-style diagonal hull, described on a different thread.