Steering of a Fjord Weekender 24

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Dirk
Inlägg: 6
Blev medlem: 09 mar 2017, 21:21

Steering of a Fjord Weekender 24

Inlägg av Dirk » 04 feb 2019, 07:00

Hy guys,
last season it seemed that i had a little bit play in my mechanical steering of my boat.

It is a Fjord Weekender 24 with two AQ 170 / 270 (Construction Year 1973)
Now i am looking for a new mechanical or hydraulical steering.
Can someone tell me which mechanical steering was mounted in this boat original.
I have no original dokumentation from the first buyer and i not want to uninstall the steering before i have solid base of information.
I want to make a calculation for the steering forces at my z-drives, but i not found a example calculation.
When i use the example calulation from Vetus for their hydraulic steerings i have much to much force / moment.
When i use a calulation with F=A*V²*Rho the force and moment is also to much.
What i need is:
- original setup of mechanical steering from Fjord Weekender 24 with two Volvos 170HP
- Calulation example for Boats with Z-Drive (the best double drive)
- How calculate the boat manufacturer / designer the steering of their boats?
- usable setup of mechanical or hydraulical steering for this boat.
It would be good if someone could send me some calculation principles for setup steering of sport boats.

Best Regards

Dirk

Lars Lundbladh
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Blev medlem: 26 jul 2003, 23:46
Ort: Sweden
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Re: Steering of a Fjord Weekender 24

Inlägg av Lars Lundbladh » 06 feb 2019, 13:09

The Steering system is usually teleflex but there are some variants. Steering is supplied from motor manufacturer in your case Volvo Penta that buy in shit and steering frome Morse or teleflex. To retrofit a hydraulic steering to Volvo AQ170 it si important to know the type of Sterndrive my gess it is either Volvo 270 or 280. The shield mounted in the stern is different 270/280 etc and fitting of steering kabel differs, you need to know how cabel is fitted and also type of steering arm.
Sizing is easy as the supplier of hydraulic system have a specific cylinder and pump for your sterndrive. You have to look for Cylinders for Stern-Drives without Power Assistance. Se links below. I might be able to assist you more if I know what type of shield/stern drive you have.

Hydraulic system:
https://www.ls-france.com/en/hydraulic- ... g-systems/
http://www.mavimare.com/en/steering-sys ... sted-.html
http://www.seastarsolutions.com/product ... ering-new/

Volvo pages, look for steering and connection components at these pages:
http://www.marinepartseurope.com/en/e-v ... Q170A.aspx

Mechanical steering types:
https://www.jamestowndistributors.com/u ... ?docId=691

/Lars
Fjord 900 Dolphin -88 /D6
Ordförande och webmaster i Fjordklubben

Dirk
Inlägg: 6
Blev medlem: 09 mar 2017, 21:21

Re: Steering of a Fjord Weekender 24

Inlägg av Dirk » 09 feb 2019, 08:03

At first, thank you very much for the information.
This weekend i will look at all.
The installed drives are two pcs of: Motor AQ 170B with stern drives 270.
I looked at the Boot in Düsseldorf for that, but all suppliers only had sets for 280 or later.
Normally i install everything by myself an i also calculate this before, but at the moment i am searching
for more information about calculation of rudder; the problem is, you find much for big ships, but near
nothing for sport boats and stern drives.
My idea is to unmount the mechanical steering and install hydraulic with the same mechanism for coupling the two drives.
So i need a cylinder with a stroke of +/- 150mm; in sum 300 stroke; this would be the easiest way.

Dirk
Inlägg: 6
Blev medlem: 09 mar 2017, 21:21

Re: Steering of a Fjord Weekender 24

Inlägg av Dirk » 09 feb 2019, 19:13

Here some pictures of the installed equipment
4QX7o4Ma.jpeg
RCHAUYSl.jpeg
T2ou2T9J.jpeg
JP9Uxb1L.jpeg
pNrTFsHs.jpeg
The stroke is +/- 150mm

Lars Lundbladh
Inlägg: 1222
Blev medlem: 26 jul 2003, 23:46
Ort: Sweden
Kontakt:

Re: Steering of a Fjord Weekender 24

Inlägg av Lars Lundbladh » 10 feb 2019, 12:33

Hi again

Maybe this is not of much help but you have a reduction kit installed. the reason is probably to make the mechanical steering to be able to increase force. I guess you have 300mm stroke on the steraing cabel and ~150 mm on the steering arm of the sterndrive?
Bild

If you look to the fore needed to for singel mounted stern drive is about 30 kpm (~300Nm) for twin installation with counter rotation the steering force is about +20% see text below.
Example of cylinder:
https://www.ls-france.com/en/hydraulic- ... 9b11b-c095
Bild

From LS Lecomble & Schmitt:
To select a steering system in our range, first determine the maximum horse power developed by the outboard motor(s) and the rotational direction of the propellers on installations with several motors.Indeed:
•For twin motor installations working in the same rotational direction, add the power of both motors (seeexample below).Whereas:
•For twin motor installations working in counter-rotation, take into account the power of one motor only + 20%

Maybe if there is room you might consider fitting a 280 bracket to be able to mount 280 type hydraulic cylinders. You must the change the steering arms. It might be a problem with if you have old type of 270 steering helmets as they have a smaller shaft diameter. Parts are obsolete and maybe used parts are difficult to find.
Bracket Volvo part #850958 Source:
https://www.ebay.co.uk/itm/Volvo-Penta- ... 1657515039

/Lars




/Lars
Fjord 900 Dolphin -88 /D6
Ordförande och webmaster i Fjordklubben

Dirk
Inlägg: 6
Blev medlem: 09 mar 2017, 21:21

Re: Steering of a Fjord Weekender 24

Inlägg av Dirk » 11 feb 2019, 07:02

Hy Lars
you guess right. It is a 300mm stroke on the stearing cabel and ~150 mm on the steering arm of the sterndrive.
I think the easiest way is to order a hydraulic cylinder 32 or 35 with a stroke of 300mm and a pump with 40 or 42cc.
Then i can change the parts and connect to the old reducing kinematic of the mechanical stearing.
Thanks very much for your help.

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