Hydro Junkie

Mart is correct, to a point. The hook is used to pull the boat's sponson down and keep the boat flat in the turns. Many boaters(myself included) prefer to use a flat blade instead of a hooked one as the angle can be adjusted, thereby controlling the amount of downforce generated in the turn. With a hooked blade, it's installed vertical so only the hook at the bottom is pulling down. There are pro's and con's to both set ups and really comes down to operator preference. There are some that will take the argument to the point that one or the other "WILL NOT WORK!!!!!!!!!!!!!!!!" Had someone locally tell me that about a fin on a Sport 40 I'm working on. Been building boats with flat blades for decades, watched many others do the same with very good results. Don't let anyone tell you one or the other is superior, try them both if needed and go with what you like

tt-r

Getting some real good information here, thanks guys
I have to say i the flat fin sounds like a good choise, for two main reasons. First you dont have to bend it witch i feel will weaken the material, second and most important the posibillity to adjust the downforce. Up to this point i only have experience with curved fins on my riggers. So i want to test flat ones too when i get my hydros ready. The building is on idle at the time(too long time) since i dont have any hobbyroom anymore.
But on to my next question When a hydro starts hopping or bouncing in corners, has that anything to do with the turnfin?

Thanks again for all the helpful info so far....

martno1fan

Mine only hops when its choppy ,love this curved fin it def keeps her from lifting in the corners i doubt a straight one would do that .Ive seen her lift a few times only for the bent fin settle her right back down,least thats what i think it was.Even in straight running when its choppy i think it helps.Best way to adjust ride attitude in my eyes is to adjust the strut height to keep the nose down .Im sure hydro junkie will prob disagree but its all good info.
Mart

Hydro Junkie

Not going to disagree with what you have personaly seen. Hopping in the corners is normally a symptom of something else. As Mart said, choppy water can cause it, though it could also be a sign of too narrow of boat, bad set up or improperly balanced boat. Something I rarely see is a boat actually "tripping" itself as it goes through a corner. This can be due to the sponson nontrip or the rear nontrip being too vertical. I've also seen boats where the right sponson runner is lower than the left, causing the boat to run funny

tt-r

Mart; when you say it like that i understand the curved fin does a great job too. I did see in your video that you really rip it up in those turns I just have too little real life experience with hydros. I ordered a UL-1 superior the other day just to have something little more "rtr" to have fun with while building my big hydros. Maybe i can gain some knowlege with that along the way.

The zipkitts are soon back in stock so then i will get started on that too. My other project is a 1/7 (aprox) picklefork. I am trying to get hold of some 2K expanding foam for the sponsons, but am having a hard time getting it where i live. Do you think i could use the turnfin and bracket from the Zipkitt? even if its a bit smaller boat than my pickle...

martno1fan

Hi mate you cant go wrong with the zippkits hydros they are quick and easy to build and run very well.Regarding your bigger hydro you could def use the zipp fin as its very big in fact Joe came up with a mod for the fin which involves cutting the fin down narrower and more curved if i can find a pic ill post it.Be carefull with that expanding foam it keeps going and going.
Mart