Speedy sponsons

[Mini Max]

Knife spoon, and cup. Tunnel boats may have a hook forward to plant in a turn. Have you seen a snow ski? Narrow in the waist and wide in the tips and tail for carving a turn. Just rolling your ankles will make a turn. Maybe that and a dollar gets a cup of coffee.

Me, I would look to venting the back of the sponsors as you would be dragging two big low pressure bubbles. I have seen a big yacht with 4,000 hp unable to get on plane because a solid swim platform had supports that end plated the transom. 4 " vent holes through the platform relived the vacuum and the boat took off.

[modracer7b]

Fins don't always get you around fastest either. I have used skid fins, bottom edge fins, retractable fins (when they were legal), center and offset fins on runabouts, chine fins, transom fins and at times no fins. I have some experience with what a fin will and will not do. Your air traps also work as part of your turning system. I was one of the first to use hydrobout fins for flat turning runabouts. I won a national outside chining a runabout with no fins, simply using the outside edge of the bottom and went from last to first around the outside of the other eleven roll up boats in the first turn. My point is that in some water conditions your sponson will be an anchor no matter what you do. If it is rough enough, the sponson will touch down and grab as will the entire outside of the boat.

[Carruthers]

I don’t know about you modracer but I usually like to use my skid fin to do the work as it’s intended and keep my sponsons from being an anchor

[modracer7b]

In a race, the most important number is the lap time. In the end, the guy that runs the lap in the least amount of time is the winner. That is why the fastest guy does not always win.

[Albert]

Modracer,
Is this like the dirt track guys turning the wheels right to make the car go left .

[modracer7b]

Of course, there are two ways of looking at that comparison. If you are trying to take a high speed turn holding a line right on the buoys, do you want to act like a spoon or a knife. The spoon may give up a little speed, but holds the turn while the knife may go a touch faster but bounces you way wide off the buoys. Now which method actually gets you around the turn faster. The faster may actually be the slower. There are many factors to consider to answer any question.

[ZUL8TR]

Head thoughts and Butt dino are subjective measures that are present

[Carruthers]

I like use use the spoon and a knife as an easy comparison on how water reacts to surfaces hold the underside of a spoon up to your kitchen tap and it will be sucked in hold a knife to the same stream of water and it will bounce off it is nearly impossible to compare the two in a racing situation but at the end of the day would you rather be a spoon or a knife

[Albert]

Maybe it’s a physiological advantage. “I believe it’s fast therefore I’m fast”.


I’ve read up on boat race it’s interesting just like a lot of things in Japan.

[ZUL8TR]

About as difficult as unscrambling an egg and getting it back in the shell as untouched! In a turn there are so many variables to isolate as fixed to determine the difference of how one particular variable changes is the problem. In a straight-a-way no problem sponsons are aired out no water drag if rig set up right. Hard to get 2 boats exactly the same even without the sponson difference. They are close to getting boats the same in Japan boat racing with Yamato engines. See link on how exact they build the engines on page 235 (scroll down) and for the boats on bottom of page 235 left click for page 236 (scroll down)

https://www.flickr.com/photos/fotois/page235

A look see at Boat racing in Japan

https://www.youtube.com/watch?v=Xqn5nuRkAxM

[ZUL8TR]

About as difficult as unscrambling an egg and getting it back in the shell as untouched! In a turn there are so many variables to deal with to isolate as fixed to determine the difference of how one particular variable changes is the problem. In a straight-a-way no problem sponsons are aired out no water drag.

[Albert]

Semi serious question...bagels aside. If someone wanted to test the performance of such a thing and had a boat that was the same specs minus the stepped sponsons how would one do it?
I know on top of the boat you could employ the string and tape method to see air flow. But measuring drag on the underside of a sponson while cornering seems tough to quantify.

[Carruthers]

These sponsons are flat in every way possible the steps help do that and eliminate the drag of rounding the pad down to the tip and the two chine angles just make it possible to achieve more angle without the weight disadvantage of a wide sponson while creating a lifting strake at the same time

[Entler]

Now do any of you all know why seagulls are called seagulls????




because if they lived by the bay, they’d be called baygulls!
just wanted to shed history and enlightenment on bagel technology

[modracer7b]

I tried round sponsons on a "A" hydro back in the 90's and the problem that came out was that the front had less stability in the turns due to less flat on the sponson. The idea was to eliminated any sponson digging when they touched down and that part worked, but the lack of stability was a handful. I did not persue the design further after trying to work with it for a season and the boat became a nationals bonfire one year. Your design is in between what I did and the normal sponson, so you may have more success than I did. The boat I worked with also had other experimental design factors built into it which may have also affected the stability, so I cannot positively blame the sponson design for the handling issue.