Phil Thomas sport 45

[Shooter]

Good write-up. The concept that John is talking about is exactly what I am experiencing. The right side mounted rudder is planting the left sponson during a left correction.

Unfortunately, in my case, the planting of the left sponson is making it easier to climb up the fin, and blow the boat over.

[Fluid]

One thing I learned long ago is that the size of the fin and rudder must be matched. If the fin is too big for the rudder the boat will eventually spin out due to excessive rudder deflection needed to overcome the fin. It takes testing to find the right balance for each hull/setup.


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[Shooter]

I have not shortened the rudder. It certainly could have been exaggerating the issue. I also have been trying to pay attention to rudder angle. Read somewhere that a tucked rudder will actually pull the transom down, rather than lift it. Makes sense.

[MarkF]

My turn fin is a good size hooked one but my rudder is a 1" strait at 4 3/4 long. It say 4" is enough but here in Las Vegas, the water gets very choppy and lots of wind. I built this boat heavy on purpose
with a bigger motor than everyone else uses and I'm using solid hardware. I'm really looking forward to running the boat.

Mark

[longballlumber]

I have not shortened the rudder. It certainly could have been exaggerating the issue. I also have been trying to pay attention to rudder angle. Read somewhere that a tucked rudder will actually pull the transom down, rather than lift it. Makes sense.

IMO... The leading edge of the rudder should be perpendicular to the set up; no angle forward or backward. If you tucking or sweeping the rudder your just putting a band-aid on a different problem. A sharp rudder is a good idea too (wink, wink, - Pete)

[Fluid]

IMO, the rudder pivot rake is another tuning aid to help the boat get through the corners. Angling the rudder blade only has a minimal effect, but changing the angle of the rudder pivot can make a big difference. Angling the pivot back will help to keep the transom up in the turns - if that is needed. With the higher performance low-lift props we can use today, something has to hold the transom up; angling the prop down slightly will help, but then that effects the boat on the straights - hopping, dragging the sponsons, etc. One good thing about angling the rudder pivot is that it has no effect on the straights.



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[MarkF]

Tuning a boat for sport is one thing and tuning it for oval racing is another. Race water gets very choppy and possible wind and I think a strait rudder will be best here. I will test and see. If not, I will put a tapered rudder on the boat to see if that helps. I know the gas hydros and riggers are using a wide and strait rudder now and it seems to work good for them. I'm using a speed master set up so a blade change is easy. My turn fin is made out of SS and is very stiff, sharp and thin. Has anybody tried or got there hands on the new swordfish X series esc?

Mark

[Shooter]

Mike - Your blood is still on my boat. Definitely not from my rudder!

Just dawned on me.....when I was testing a few weeks ago, Tom pointed to my rudder and we noticed the bottom screw had loosened. It changed the pivot angle upwards. This may have been exaggerating my issue by adding more lift and planting the left sponson harder, causing the boat to ride up the fin.

[MarkF]

Well I finally got the boat all done. I head for the pond tomorrow and get the first run in and see how she does.

Mark

[rol243]

looks very nice i must say. also good to see you have the rudder on the correct side of transom.

[T.S.Davis]

I don't know. I went with the rudder where the designer said to put it. Same place the two lap record holder has it. To each his own though.

Mark, looks good. I never thought of using the pocket to house the speedo. Great idea. Gives more CG play room. Might want to restrain that water line on the trans though. I chopped mine off on the Whip a couple times with it crossing over the prop.

[MarkF]

You're right about the water line Terry. Cut clean in half and the boat was stable the whole time.
I will say this, the boat hauls and turns awsome. I set everything up per the instructions, except for rudder, but the boat wants to hop a little until I give it the gas and then it smooths out. Prop is an ABC 2316. I played with strut adjustments and lower made the hop worse. I have a touch of postive on the strut and that seemed to help but very happy with speed and turning so far. No disappointments hanging the rudder on the right. I only got one pack through the boat so plenty of testing to do. I will get some video up when I get some. I got the cg 1" behind the sponsons. Has anyone played with there cg and where did you end up at?

Mark

[rol243]

i am considering a sport hydro but not sure which one to get. i do have the gas powered Blazer Whiplash and have seen the electric 21 size fe version which looks good , if it performs as good as the big gasser it would be a hrad sport hydro to beat in oval race trim. what brand is your sport hydro MarkF ?

[RandyatBBY]

https://forums.offshoreelectrics.com...rt-Hydro/page6

[Fluid]

....what brand is your sport hydro MarkF ?

It's in the thread title - Phil Thomas Sport 45.

Yes, the .21-sized Whip is an awesome 4S race boat. It can be beat - I've done it - but driven well it is an excellent competitor.


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