Trimming a 44" 90 Seaducer

[Ian Inverarity]

I have built four 44" 90-100 Seaducers, the first for myself and the next two for friends. Those 3 worked very well (I test drove the others), however I smashed mine recently so built another. This new boat runs much looser in turns and down the straights than the other 3 boats I built. :huh: With the new boat I used the engine, radio box, all hardware and props off my old boat and put everything in the same place, basically I built a replica of my first boat. My old hull holds the current Australian 2 lap record.

I started with the settings I used on the old boat and found it ran too loose. I then kept lowering the strut to try to fix the loose running and it hasnt really helped. Why does this hull run different to the other 3 when I built it the same? Any ideas on how to trim the boat down? :unsure:

 

[Tom Foley]

I have built four 44" 90-100 Seaducers, the first for myself and the next two for friends. Those 3 worked very well (I test drove the others), however I smashed mine recently so built another. This new boat runs much looser in turns and down the straights than the other 3 boats I built. :huh: With the new boat I used the engine, radio box, all hardware and props off my old boat and put everything in the same place, basically I built a replica of my first boat. My old hull holds the current Australian 2 lap record.

I started with the settings I used on the old boat and found it ran too loose. I then kept lowering the strut to try to fix the loose running and it hasnt really helped. Why does this hull run different to the other 3 when I built it the same? Any ideas on how to trim the boat down? :unsure:

you might double check the turn fin to see if it is dead parralel to the keel (90 deg. to the transom ) Try a tick of negative , I mean an RCH on the strut . Also try 3 -4 ounces of lead directly under the motor as an experiment .

 

[Ian Inverarity]

Tom,

I am a bit loathe to set the strut with negative angle, on the old boat when I did this accidentally the boat would dunk. I worry that adding more weight may have the same effect! :unsure:

Has anyone tried longer rudders to trim Seaducers? :huh:

 

[SayMikey]

Tom,

I am a bit loathe to set the strut with negative angle, on the old boat when I did this accidentally the boat would dunk. I worry that adding more weight may have the same effect! :unsure:

Has anyone tried longer rudders to trim Seaducers? :huh:

Do you still have the old boat? If so match the hook on the bottom to the new boat. Try a piece of radio box tape running along the transom the 3m tape if that helps you need to massage the hook but dont over do it

 

[Ian Inverarity]

Mike,

I dont still have the old boat to compare to unfortunately. Is there variation in the hook between mouldings?

I will try the tape but I am not sure what a long term fix would be.

Ian.

 

[SayMikey]

Mike,

I dont still have the old boat to compare to unfortunately. Is there variation in the hook between mouldings?

I will try the tape but I am not sure what a long term fix would be.

Ian.

First you want to rule out the hook look at one of the other boats most of the hulls are dead on but once in a while you get one that needs a little help.

 

[Ian Inverarity]

I may be able to get hold of my old hull, but say I do find a difference in the hook, what can I do about it on the new hull? :unsure:

 

[Jerry_Crowther]

Can you send me a few pictures of your set up?

Are you sure you do not have any positive in the strut?

Jerry

 

[Ian Inverarity]

Jerry,

Thanks for replying, I will take some pics tonight so you can see the setup, but as I said the setup is the same as my old boat because I used the hardware from the old boat! :huh:

I am pretty sure the strut has no positive, I will get pictures of that too.

Ian.

 

[Ian Inverarity]

Jerry,

Pics of the original boat:

http://www.intlwaters.com/index.php?app=gallery&module=images&section=viewimage&img=5105

http://www.intlwaters.com/index.php?app=gallery&module=images&section=viewimage&img=5106

Pics of new Seaducer:

http://www.intlwaters.com/index.php?app=gallery&module=images&section=viewimage&img=5107

http://www.intlwaters.com/index.php?app=gallery&module=images&section=viewimage&img=5108

http://www.intlwaters.com/index.php?app=gallery&module=images&section=viewimage&img=5109

http://www.intlwaters.com/index.php?app=gallery&module=images&section=viewimage&img=5110

 

[Jerry_Crowther]

You have the strut way to high. The bottom of the strut should be about 1/8 above the bottom of the boat. Also I see you have a square drive set up. That will also make the boat run loose. I would lower the strut down to about 1/8 above the bottom and that should tighten the boat up.

Jerry

 

[Ian Inverarity]

Jerry,

Thanks for looking! B)

As I said in my first post I have tried the strut deeper, and I didnt get an improvement. In the pics of the new boat the strut is where I used to run it on the old boat, which ran fine, about 5mm up. I have tried it at about 1/8"

As for the square drive, I dont want to get in an argument about that but after running the old boat for about 1 year I made the square drive strut for it and found no change at all in the handling. I was very careful to duplicate the prop position with the needle roller strut. I raced the old hull for over a year with the needle roller strut and the handling was fine.

Ian.

 

[BB Mods's]

Id like to have one of them picco jackets and head buttons for my 91rs, any chance you have a extra set to spare?

 

[Ian Inverarity]

Tommy,

The silver cooling jacket in the first pic of my old boat is from a PIP A100, these were made with either painted silver or pale green. They have the same head bolt pattern. There was also dark blue painted versions and red painted versions, I have left-overs of all but the blue ones. However the head buttons are completely custom made by myself to suit the RS engines and the A motor cooling jackets. B)

The polished cooling jacket in the pic of my new boat is a new design I made up to reduce weight and water cooling volume. The jacket and custom button to suit is 1/2 the weight of the CMB cooling jacket and button. Also there is no cooling on the upper section of the case and no water on the head shims or head screws. There are no spares. I still have too much cooling volume even with only a 1mm water outlet and cooling the exhaust header first. :blink:

 

[BB Mods's]

Thanks for the info!

 

[Ian Inverarity]

I seem to have found the issue with the new boat running loose. I borrowed my old hull and found the CG on the new hull was at least 1/2 " further back, even tho I used everything out of the old boat to make the new boat and mounted it in the same place. So I have added weight near the nose and the new boat runs great now. B) Even with square drive..... :blink:

 

[DaveMarles]

You have the strut way to high. The bottom of the strut should be about 1/8 above the bottom of the boat. Also I see you have a square drive set up. That will also make the boat run loose. I would lower the strut down to about 1/8 above the bottom and that should tighten the boat up.

Jerry

How will a square drive make a boat run loose?

Dave

 

[Tom Foley]

You have the strut way to high. The bottom of the strut should be about 1/8 above the bottom of the boat. Also I see you have a square drive set up. That will also make the boat run loose. I would lower the strut down to about 1/8 above the bottom and that should tighten the boat up.

Jerry

How will a square drive make a boat run loose?

Dave

I guess the theory is that the line of drive force is pushing on the bottom rear of the strut rather than at a point closer to the CG . Why anyone would want to mess with all the associated set screws and bs thrust washers etc rather than a standard flex shaft i'll never know but thats a Warm Beer / Cold Beer situation !!

 

[Joe Warren]

I have built four 44" 90-100 Seaducers, the first for myself and the next two for friends. Those 3 worked very well (I test drove the others), however I smashed mine recently so built another. This new boat runs much looser in turns and down the straights than the other 3 boats I built. :huh: With the new boat I used the engine, radio box, all hardware and props off my old boat and put everything in the same place, basically I built a replica of my first boat. My old hull holds the current Australian 2 lap record.

I started with the settings I used on the old boat and found it ran too loose. I then kept lowering the strut to try to fix the loose running and it hasnt really helped. Why does this hull run different to the other 3 when I built it the same? Any ideas on how to trim the boat down? :unsure:

I have built a few 44 Seaducer mono`s. Engine & Fuel tank location Must be on specs. A Bent Rudder Blade will make a Boat Loose, A Modified Prop that kills lift will make the boat very loose, Especially mods in the trailing edge of the prop. I run a X467 octura prop. Also You will tighten the boat up when the strut goes DOWN. Keep the angle the same as the bottom of the boat. If all else fails Install a stk length rudder blade. A Loose hull is easier to tune than a Hull that is too tight....... hope this helps you out.

 

[Ian Inverarity]

I have built a few 44 Seaducer mono`s. Engine & Fuel tank location Must be on specs. A Bent Rudder Blade will make a Boat Loose, A Modified Prop that kills lift will make the boat very loose, Especially mods in the trailing edge of the prop. I run a X467 octura prop. Also You will tighten the boat up when the strut goes DOWN. Keep the angle the same as the bottom of the boat. If all else fails Install a stk length rudder blade. A Loose hull is easier to tune than a Hull that is too tight....... hope this helps you out.

Joe,

As I posted above changing the CG seems to have fixed the issues I had with my new boat. Before I did that I did try a longer rudder and found the boat was better in turns but not better on the straights and would stuff at high speed. Thanks for the tips tho.

What prop mods to reduce lift have you found dont work? I have found that higher lift props make the boat handle poorly indeed and always try to reduce prop lift.