Fin set up ?

[SPUN1]

Just wondering what the reasoning is with fin set up. Side by side, front/rear or single fin. How do they difer from each set up ? The pic shows my set up under the 63 Rayson.

[lebel409]

The single fin seemed to be used on drag boats, and double fins on circle boats and pleasure craft, although each manufacturer had their own ideas about how to set things up.

[SPUN1]

The single fin seemed to be used on drag boats, and double fins on circle boats and pleasure craft, although each manufacturer had their own ideas about how to set things up.

Thank's for the info.:)

[no longer here]

Spun 1,
409 has a handle on it. Your boat has two fins inline. Ski boats, SK's, circle boats, marathon boats,...any boat that has to turn, especially at speed, needs two fins. Think of them as the pivot that you turn AROUND.
I'm told that when circle guys set up their race boats, they find the center of balance to their fully loaded hull, and THEN, mount the fins right there. So they're a turning aid, more than straight line stability.
Drag race hulls, especially today, usually have only one fin, they don't require turning,they don't want the extra drag, and because they're not racing in choppy water, the fin doesn't need to be very deep, just enough to hold a line.
Just as the two fins will help you to turn, and keep you from sliding, circle racers used to (maybe still do) bolt a small fin(about 6' long and 3' deep) to each of the outer edges of their cav plates, called "skid fins", which helped keep the back end from spinning out from underneath you in a tight turn . Your boat is fine as is! Spike

[RiverRacer]

Fins will cause drag in the water, that's why drag fins are short and usually not in the water on a pass. Circle boats need deep fins for turning and need two of them. Now as far as those little fins on the plates goes they are totally worthless think about it, the only time the boat will spin out is when the tail comes out of the water, now when the boat comes out of the water guess what else comes out of the water, that's right the fins are in the air and they don't do $hit!.. Way back when I built my D'Cucci everyone said I needed them so not knowing $hit I listened and put them on, first time I was aggressive in a turn I spun it around same as when I didn't have any, LOL...

[no longer here]

River Racer,
Now, this is an interesting subject. I wonder if the skid fin thing is even put in use today by modern circle type boats. Certainly, as you said, everyone used to run them, but I'm basing this on my observations of boats from the sixties.
Nicson Marine cataloged them. I used to own a Hallett long deck circle boat(skiied with it), and it came with the skid fins (it was a '67). I never spun it, but I've never spun any boat, with or without skid fins.
I wonder,........... are there any older, or , newer circle type boat owners (or racers)out there who have an opinion, or experience, whether or not to run them, that you'd like to share?
Spike

[RiverRacer]

Spike, nobody uses them anymore unless they are already on there, on a new boat nobody bothers with them unless they are old school and still belives in them!... To spin a boat you have to be really aggressive and stick the nose in deep so the tail will come out of the water, otherwise it won't spin out!..

[Florida Inboards]

Great discussion.
What comonly is the depth of the fins and are they drop thru type on the circle boats. My old Ricshaw has a set off of a current Ski Nautique. The boat gulps and slides a lot trying to turn at anything above 30 mph in a left turn and tends to turn to the right far better. That though may have more to do with prop rotation. Still I would like to make this boat turn better. The original fin was a large Aluminum single fin. It was bent and gouged and need replaced.

My 08 Ski nautique can spin out, swap ends at will! It is kinda fun to do.

[RiverRacer]

Race boat stuff is all drop thru, 6"-7" is normal!. Turning better one way is from prop torque, reversing rotation will make it turn better in the opposite direction!. More fin may help some, but it'll still want to turn to the right under power!..

[canam10]

River Racer,
Now, this is an interesting subject. I wonder if the skid fin thing is even put in use today by modern circle type boats. Certainly, as you said, everyone used to run them, but I'm basing this on my observations of boats from the sixties.
Nicson Marine cataloged them. I used to own a Hallett long deck circle boat(skiied with it), and it came with the skid fins (it was a '67). I never spun it, but I've never spun any boat, with or without skid fins.
I wonder,........... are there any older, or , newer circle type boat owners (or racers)out there who have an opinion, or experience, whether or not to run them, that you'd like to share?
Spike

Spike,
I can't speak for any other hulls but I had the "skid fins" on my Biesemeyer. I have to agree with Art, they are totally wothless. I can turn the boat so hard the fins are bent flat to the plate, after every heat of racing. I have had several sets on the boat, some custom made and guaranteed not to bend out of different materials, all with the same result. In all the heats I have raced this boat I can't say that I ever noticed a difference. Like Art said nobody runs them now. Tim

[canam10]

Just wondering what the reasoning is with fin set up. Side by side, front/rear or single fin. How do they difer from each set up ? The pic shows my set up under the 63 Rayson.


Man, I think I'd open up that channel a bit as to not bang the fins into the trailer loading and launching it.

[Wannabe]

I spoke with a few guys over the years about the fins on the cavitation plate. One guy said something like this; "Awww, they don't do crap in the turns. But if you set the boat back on the rocker, you can tell at 120 if you have them or if you don't. It drives much more stable in the straights. That is why I will aways run them."
Also, I saw more boats this weekend with them than I did without them. Which new boats are running without them?

[canam10]

One guy said something like this; "Awww, they don't do crap in the turns. But if you set the boat back on the rocker, you can tell at 120 if you have them or if you don't. It drives much more stable in the straights. That is why I will aways run them."

Well Damn there's my problem !!! With SS power I don't think many of us, if any, ever saw 120 even on the longest courses. I also think in any boat running 120 you'd better be running with the plate up as far as possible and running very free. With all the white water under the plate I can hardly believe a 3" fin is going to find any clean water to dig into. So in my opinion they don't do crap especially when their bent flat from going through the fist turn without letting off the gas.

[RiverRacer]

Well Damn there's my problem !!! With SS power I don't think many of us, if any, ever saw 120 even on the longest courses. I also think in any boat running 120 you'd better be running with the plate up as far as possible and running very free. With all the white water under the plate I can hardly believe a 3" fin is going to find any clean water to dig into. So in my opinion they don't do crap especially when their bent flat from going through the fist turn without letting off the gas.

You're absolutely right there!..

[SonnyGlide]

well, I finaly got the answer to my thread on Fins:o

[gfinishline]

I've been reading this and I just want to ask... If the plates are "hard/down" in the water and the 'plate fins" are straight ahead, while the rudder is at a 35 degree angle/turn, WHO is steering the boat? Also, I've rigged a few circle/ski/play boats with 16" (front to rear) and 9" deep single fins. None of them ever skipped in the turns. I feel the THINER and DEEPER the fin, the better it works for turning. Big thick cast bronze deals, don't seem to do the same kind of predictable job. OH and a nice "SK" rudder doesn't hurt either.

[canam10]

I've been reading this and I just want to ask... If the plates are "hard/down" in the water and the 'plate fins" are straight ahead, while the rudder is at a 35 degree angle/turn, WHO is steering the boat?.

Who or what ??

[lebel409]

The cav plate fins merely keep some traction (if), the rudder makes the turn.

George...cav hardware question.

The old down levers on my boat were all equal length. The problem was the down levers were not compatible with standard turnbuckles. I bought a second boat with modern turnbuckle compatible levers.

I took everything apart before I noticed...all the levers were different length.

The boat is flywheel facing forward. Should i put the longest pins on the inside or the out side, I'm assuming longest 2-4-6-8 on the left?

Thanks!

[RiverRacer]

The cav plate fins merely keep some traction (if), the rudder makes the turn.

Trust me they don't do $hit!..:D

[SPUN1]

well, I finaly got the answer to my thread on Fins:o

Me too! Lot's of very good info here and the people are cool also.:)

[SPUN1]

Man, I think I'd open up that channel a bit as to not bang the fins into the trailer loading and launching it.

Yeah i've considered that but have'nt had much trouble with it.:)

[lebel409]

I believe you Art!

Any ideas on the unequal length pins?

[RiverRacer]

I believe you Art!

Any ideas on the unequal length pins?

I take it you're talking about the levers on the bar, usually different lengths are to componsate for a longer plate in the center to get even travel, also I've seen some runner bottoms that use longer ones on one side to get more travel on one side for the torque, on circle boats we just adjust the corners!..

[lebel409]

The plate is square across the bottom, but it has a very shallow V...1 1/2" in 36"...more difference in the levers than the transom...

Would the control be more effective on the inside at the prop or at the outside edges.

[George1301]

Art,
I have the same fins mounted on the rear feathers as you mentioned... First time out I thought they did "help" the stability, but have to agree with you....Second time out I had not noticed but one was MIA... no difference..! BTW... that ring works great..!

Geo

[RiverRacer]

Art,
I have the same fins mounted on the rear feathers as you mentioned... First time out I thought they did "help" the stability, but have to agree with you....Second time out I had not noticed but one was MIA... no difference..! BTW... that ring works great..!

Geo

Glad to hear it works for ya!..:cool:

[RiverRacer]

The plate is square across the bottom, but it has a very shallow V...1 1/2" in 36"...more difference in the levers than the transom...

Would the control be more effective on the inside at the prop or at the outside edges.

I would use all the same length arms myself and make it simple and right, but that's just me!..

[gfinishline]

"Lebel 409" The longer levers go to the outer edges. Some guys like the hull "stable" in the turns and the short levers allow the hull to 'climb higher' on the straights. Just like the Sanger "gull wing" hull bottoms, it was done for stability and straightaway speeds. The only problem comes in when some of the levers start to break. You can 'twist' an aluminum plate 'just so much' much durring "down plate' use. Some builders just cut out the center few inches of plate, this allowed the nose to rise and gain straightaway speeds. I would decrease the diameter of your prop (up the pitch) , then use levers that are more in the same overall length. If the center levers are 1 1/4" long, use them on all but the last lever on the right (starboard) outside place. There I would use a 1 1/2" lever. Cavitation plates ARE DRAG!!! You want to use them as little as possable! Get your plate up above the hull bottom and know that you are not "racing with the brakes on"!

[lebel409]

The levers are 8 different lengths, each about 1/4" longer than the next.

So my plan is to go longest (8) to shortest (1)

8 6 4 2 1 3 5 7

My other thought was to go

2 4 6 8 7 5 3 1 because of the V.

New levers are $400...so not likely for a while...:D


Thanks for your help Guys!

[RiverRacer]

New levers are $400...so not likely for a while...:D

Your shopping at the wrong places there bud, there less than $200 for the longest ones!..:D

Rex! (http://www.rexmar.com/page139.html)

[lebel409]

??? I went in there and asked for turnbuckles and levers...about $800...I about crapped...so I bought a spare boat.

Maybe the new catalog will have updated prices:D

[George1301]

I would go with the 246 sequence to follow the VEE...
On mine... I found that adjusting the two outmost a bit longer helped stabilize to a faster speeding ticket... :)

Geo

[gfinishline]

$800? I'll get out my Glenwood book and see what I can do. For a "2 piece plate" I would NOT run all that stagger in the lever lengths. It will just bind and start breaking stuff. What do you have and what do you want to end up with? I've got a few pieces and I know how to make all of them. PM me if you need help with parts.

[RiverRacer]

??? I went in there and asked for turnbuckles and levers...about $800...I about crapped...so I bought a spare boat.

Maybe the new catalog will have updated prices:D

Pull the price list and see for yourself, even turnbuckles unless they are super long they are no where near $800!... Hell just buy some round stock and make some levers!...

[lebel409]

Thanks Art and George!

I'm getting the junk back from the polisher today or so, so I'll see how it all lines up before bugging you about specifics...

I got the hardware from GR8White...the boat that has a fiberglass or phenolic downplate. No idea how that boat ran, but maybe the soft plate had to do with the unequal levers?

I have a lathe, but no mill ( and only kinda know the lathe).

[gfinishline]

If you think the rear end of the plates will 'flex", use an aluminum angle under the plate pads on each side. Just remember, the straighter "up and down" the turnbuckes are, the BETTER they work. Just (exactly) what are the lengths of your LEVERS?

[RiverRacer]

No idea how that boat ran, but maybe the soft plate had to do with the unequal levers?

It didn't run, you should have got new/right stuff to begin with!.:D

[lebel409]

Alright, checked my father inlaws boat....

His are the longest on the right (flywheel forward boat) and get shorter as you go to the right. His are all different lengths except the smallest two.

He also said that the hull is set up with a little more rocker on one side and a little hook on the other...so that even thought they run good in circles, if you reverse the motor like most circle boats you'll loose the advantage of the bottom.

His levers are longer than mine, but both shorten by about 1/8" each...

[RiverRacer]

That's because it was designed to run off the flywheel not the front, total opposite!..

[gfinishline]

The LeBell's flats that I remember have two plates. To me this means the hull has a slight V in it's bottom. On the straights, I want to ride on ONLY the center keel and the center 4 turnbuckles. On the turns, I want the entire plate in the water. Next, I would say "generally" that drag boats mount the strut behind the motor and circle boats mount the strut under the motor. I would also conclude that with the prop more forward on a circle boat set up, when the plates are down, more of the plates and hull bottom surfaces are in the water than a drag boat set up. Further more, I would say that "I feel" right hand prop rotation would not effect the "hook/rocker" personallity of the hull (as far as turning) In fact, if the "hook" is right of center, the last outside lever would not need to be the longest. With the "hook" and plate set to the hull bottom on the outside right, you would only want to make the plate 'extend the hook', and not go deeper and create more drag. (maybe even pull hard right) I think I put the plates down going into the turns to "settle the boat", "maybe drop a little speed" and most of all, "keep the fin and rudder in the water". Would be interesting to "test one out", with a circle boat (right hand) set up in it.

[Bigblock]

Please forgive my arrogance gfinishline but is "Hook" a part of the boat (cav plate or maybe the small fixed plate between the 2 cav plates) or a characteristic of the boat (feel or attitude)? :confused:

My ride is a V bottom with a 454 up the back , my strut is mounted below #3 & 4 cylinders.
Dont know why i just wrote that.:o

Dont laugh too much at me for thinking cav plate if im wrong,
i am a newbe :rolleyes:

Bigblock

[lebel409]

Even though flatbottom are mostly flat...there is shape down there...

Hook is concave and mostly to be avoided. Rocker is convex and the arc of the convex is where the boat rides...but this varies greatly between boats.

George, lebels are a very shallow V...1 1/2 inches in 3'. On all the lebels I've seen the motor is back...Father inlaws blown BB 130 mph + drag boat...stock motor location.

[Bigblock]

[QUOTE=lebel409;7505]Even though flatbottom are mostly flat...there is shape down there...

Hook is concave and mostly to be avoided. Rocker is convex and the arc of the convex is where the boat rides...but this varies greatly between boats.


Sorry mate, i am simple.
Could someone draw me a picture :D:(:o

[gfinishline]

OK! I need to remember WAY BACK IN HISTORY. My friend Terry Thompson and his buddys had a TFF LeBell named "Rambunkshus" ?? I think. Anyway, Terry also had a tunnel ram LeBell for his house on the river. I have worked on those hulls in the past and I (kind of) remember what they looked like. Between my mentors, "Big Al Weiss with blown gas early Hemis, and Rocky Childs with blown fuel early Hemis", I was asked to "help out' on the TFF. The boat ran quick but lacked top speed, and was destroyed in a violent flip in northern Calif. in it's third year of racing. Mounting the motor "way back" was common in those years, but not what we do today. I have worked on Lebell flats and cruisers, 21' whaler (the only one), and Tom Macurrie's (Buick Riviera Wagonmaster) 21' blown cruiser. Bud built some "damned strong hulls", and many are still running! But that doesn't mean we can't improve on the rigging!!!

[AquaCraft]

River Racer,
Now, this is an interesting subject. I wonder if the skid fin thing is even put in use today by modern circle type boats. Certainly, as you said, everyone used to run them, but I'm basing this on my observations of boats from the sixties.
Nicson Marine cataloged them. I used to own a Hallett long deck circle boat(skiied with it), and it came with the skid fins (it was a '67). I never spun it, but I've never spun any boat, with or without skid fins.
I wonder,........... are there any older, or , newer circle type boat owners (or racers)out there who have an opinion, or experience, whether or not to run them, that you'd like to share?
Spike

http://www.v-driveboat.com/vweb/attachment.php?attachmentid=817&stc=1&d=1217863332

Spike,

'Check out Wannabe's race pix from this weekend at Long Beach. 'Seems to be a number of boats running plate fins; maybe some of these racers have some theories to share?

Also, I think pix like these illustrate the importance of a rudder that runs deeper than the prop; 'tail-ends can have a tendency to walk sideways if the prop returns to the water first.

Thanks again to Wannabe for the great photos.

[RiverRacer]

The theory behind those fins were to prevent spinning out in the turn, soon found out that they have no value at all, they just fold over in the turns anyhow, if you spin out the tail is out of the water, guess what else is out of the water, the fins!.. Nobody uses them anymore, only reason you see them on older boats is because they are there, if you take them off the plates are messed up with holes!..

[Terrible toy]

Race boat stuff is all drop thru, 6"-7" is normal!. Turning better one way is from prop torque, reversing rotation will make it turn better in the opposite direction!. More fin may help some, but it'll still want to turn to the right under power!..

Sorry Art, don't understand the logic of why, after you get a good head of steam up and the boat on a perfect set, you would want to turn the thing.:D:D

[Carnivalride]

Sorry Art, don't understand the logic of why, after you get a good head of steam up and the boat on a perfect set, you would want to turn the thing.:D:D


ROFLMAO :D:D

[RiverRacer]

Sorry Art, don't understand the logic of why, after you get a good head of steam up and the boat on a perfect set, you would want to turn the thing.:D

Elementary my dear Watson, it's to go back where you came from!.. LMFAO...:D:D

[Terrible toy]

Elementary my dear Watson, it's to go back where you came from!.. LMFAO...:D:D

Oh! that makes sense. Not sure the officials at an IHBA race would approve of driving back down track however.:D:D

[RiverRacer]

Oh! that makes sense. Not sure the officials at an IHBA race would approve of driving back down track however.:D:D

Ahem Bill, at Fireturd they run the circles on the drag course!..:D

[Hurricane]

I've been reading this and I just want to ask... If the plates are "hard/down" in the water and the 'plate fins" are straight ahead, while the rudder is at a 35 degree angle/turn, WHO is steering the boat? Also, I've rigged a few circle/ski/play boats with 16" (front to rear) and 9" deep single fins. None of them ever skipped in the turns. I feel the THINER and DEEPER the fin, the better it works for turning. Big thick cast bronze deals, don't seem to do the same kind of predictable job. OH and a nice "SK" rudder doesn't hurt either.

George, I hear/read a bit of Bob Warren in this....Thanx:)

[gfinishline]

What are the "rudder rules" in the APBA rulebook? Can you run more than one? Can they be placed anywhere on/under the boat? Can they be moveable?

[gfinishline]

I must say that I learned a lot of good info from a few great people. Bob Warren (and Steve) are at the top of my list. Everything they did was finished off to perfection, no rough edges, even way under the deck. I sure wish I had the molds for Bob's flat boat right now. I loved mine. Now that I can afford to, I would lay them up with the finishing touches, just as Bob and Steve did. Some call it "old school", I call it "lasting quality". Thanks for bringing up Bob's name, "one of the best"

[RiverRacer]

Nobody has ever thought about that, so it don't say you can and it don't say you can't!..

[gfinishline]

OK, I was out with some friends that had SeaDoos. The models they had were sporting some "chine rudders", on both sides. After seeing them I thought, "this can work for flat boats too". Mount one on the port end of the transom. It is out of the water while the plates are up, but drops down into the water when plates are down. The key to making this work is a "drag water pickup" system that I devised (way back) as a 'safety brake' for drag flats that got too high. Go down on the plates and the port rudder drops into the water, creates a drag and is controled by the steering. You would see guys going DEEP into the turns like back before whirlaways. The extra rudder would be off set by a 12" deep single fin up front. (12" deep X 16" long)

[RiverRacer]

Got a boat to try it, it's only money!...:D