View Full Version : SeaStar Hyd, Steering

03-10-2011, 02:05 PM
I have a complete new Teleflex "SeaStar 1 " internal hydraulic steering system here with a first generation surface & behind dash mounted helm pump, inboard-style 1 1/4" diameter aluminum cylinder, swivel cylinder mount & rod end heim joint, black plastic lines & special compression fittings etc.

I also have several bottles of the older red SeaStar fluid & rebuilding kits for both helm & cylinder + air bleeding kit!

I bought three of these "Seatar 1" inboard systems for several restoration projects we had here about 25 years ago~~~

The "SeaStar 1" was just introducd at this time !

We used two systems on standard conventional inboards & rudders with geat success.
These were used on classic mahogany speedboat restorations Dad & I did.

We hid the helms under the older original steering bezels along with making a steering wheel adapter..

The third complete system I still have today was never used !

I think this system cost about $700. ~~~Twenty years ago !

How well would this "SeaStar 1" system work with an old original Volvo-Penta 270-280 out drive ?
This should easily replace the old Teleflex push-pull cable steering system I would think ?.

Would this give me a more stable steering system ?
How about at Donzi 18 top speeds ?

I like the fact that the steering systems actually locks with internal check valves when you stop turning the steering wheel and let go of it !

I know it's not really a true racing system~~~

But would it work very well for speeds up to say 65 MPH ?

How do I tell what the Cubic Inch output is of this New Old Stock helm pump ?
I know they made several helm pump outputs.
I believe this is the lowest ?

Is there a part # on this helm that would tell me it's output capacity lock-to lock ?

Has anyone actually used a "SeaStar 1" internal hydraulic steering system on an old Volvo 270-280 powered Donzi 18 ?

If so~~~
How well does it work on an I/O Donzi at higher speeds ?

03-10-2011, 02:44 PM
Teleflex makes an outdrive version of the Seastar, sort of.
It's made for power steering. I had one on the Minx.
It'll be different than what you have, unless yours is a V-drive....I don't remember.
If it's an outdrive and unboosted, it's a bear to turn to the right!!!
It uses the Teleflex hyraulic helm, and has two cylinders at the inner gimbal assy. One is powered by the helm, the other is powered by the Saginaw pump on the engine.
It uses a shuttle valve system similar to the standard Merc system.

03-10-2011, 03:42 PM
Don't know what system you have, but my classic 18 came with a Seastar internal system as you describe on a Bravo 1, it was ok and did ok but I took it out and added a dual full hyd Lathem system couple years back the Seastar system was a bit harder to turn than my current set up but did well over all, I'd say for 65 mph it would be a step above just a cable. Because it was an internal system there was a tad bit of play in it where the ram mounted to the tiller arm and in the tiller arm itself I thought maybe 1/8"-1/4" maybe. There was a pretty big difference in my old system compared to what I have now, but I'm also running a shortie and run a lil above the 65mph mark as you stated. I'd think you'd like the seastar over just a cable.

03-10-2011, 04:03 PM
I use a teleflex/hynautic system in an 18 with an old Volvo. It gets rid of all the slop in the cable and helm, but the flex of the yoke to helmet outdrive remains. I use an unbalanced 9" cylinder and the greater volume side helps to turn against the prop torque. It made driving the boat MUCH better. Above 65, the flex still makes things interesting, but a well adjusted small torque tab on the outdrive helps.

03-10-2011, 05:38 PM
Thank's guys~~~

The SeaStar inboard steering cylinder I have is a balanced unit with a cylinder rod comming out of both ends.
Equal hydraulic pressure is then applied in both turning directions.
I can see where it would be much harder to steer against the prop's normal torque steer.

I guess I could always look for the un-balanced internal style I/O cylinder to counter-act this prop rotation torque steer issue ?

03-10-2011, 06:54 PM
This link might help you find what you need

03-10-2011, 07:55 PM
I believe mine was a balanced system also, still have the ram and helm if anyone needs one

03-10-2011, 09:17 PM
Here's a thread about installing the boosted Mercruiser version in the Minx;


03-17-2011, 09:50 PM
If I used the New Old Stock SeaStar I helm and 1/1/4" balanced inboard style cylinder connected to my old Volvo 270 tiller arm & it's steering helmet would the old Volvo drive's trim tab not zero-out most of the prop's one direction torque steering effort issue.

Do most old Donzi/Volvo users NOT use this old behind the prop torque trim tab ?
This was really designed to help negate prop torque steer.

Most of these tabs I see on outdrives and outboads are not adjusted correctly !

Many don't install the zinc style tabs at all !
Many tabs are long gone & missing .

There is a feellow in Ocean Cty NJ that developed MS a few years back and had some muscle & arm strength issues in the last few years~~~

My late father went out and bought & retrofitted a bigger diameter steering wheel on this fellows SeaStar equipped single high powered outboard boat.

The bigger steering wheel was a cheap & quick band-aid fix for his
heavy effort steering problems.
THis fellow was now able o use is boat again !

You would be shocked at what a 3" larger steering wheel will do for you to lessen your steering wheel effort !

03-17-2011, 10:24 PM
The boosted system I had on the Minx had a helm that required between 4 & 5 turns......it would keep you really busy!
One day the engine threw the P/S pump belt and I found it was managable, but it was a lot more fun when it was all working correctly.
Nothing wrong w/a larger wheel, but keep in mind you might not fit behind it!!!!!
These things aren't real roomy, but there's nothing wrong w/trying it.

03-17-2011, 10:30 PM
You have never seen me~~~
But I am 6 foot & 265 lbs~~~
I'm not exactly a small guy to fit into my 36" deep, dash to seat back, project benchseat 18's small cramped cockpit !

That is exactly why I am looking for a bigger Benchseat Hornet !

03-18-2011, 04:26 PM
I used a SeaStar Helm pump o my 18' Classic, I had a Single External 1 1/4" Marine Machine Cylinder. The Helm Pump was 1.7ci. It Took 9 Turns Lock to Lock, I ended up getting a 2.4ci and it took it down to about 5 turns which was good on a 70+mph boat. The wife refused to drive it while it had the 1.7, I guess I don't blame her, Docking was fun fun....

03-19-2011, 08:17 PM
The real problem I see with the simple SeaStar is far too many people use too large a diameter steering cylinder along with it .

The old NOS package I have has a balanced 1 1/4" steering cylinder along with the small 1.7 ci.in. SeaStar I output Seastar I helm unit.
I have no idea how many steering wheel turns this set-up would give me lock-to-lock ?

Since the old Volvo 270 is now locked-up with rust and won't move I can't mock it up to test it !

I suspect I will possibly need to look for a larger 2.0 or 2.4 cu.in. output helm to bring the number of lock-to-lock turns down to a reasonable & safe steering lock-to-lock limit for a performance boat like the Donzi 18 ?

03-19-2011, 08:49 PM
Of course the cylinder volume is easy, cylinder area minus the rod area, times the stroke.
Then divide the cylinder volume by the helm per revolution volume gives turns lock to lock.
Overall, I REALLY don't think this is a good setup for you.
You could use this cylinder w/a Char-Lynn helm and a Saginaw pump.
That would be a good, reassonably priced setup.

I can explain how to do this, if you want.

03-20-2011, 12:10 AM
Of course the cylinder volume is easy, cylinder area minus the rod area, times the stroke.
Then divide the cylinder volume by the helm per revolution volume gives turns lock to lock.
Overall, I REALLY don't think this is a good setup for you.
You could use this cylinder w/a Char-Lynn helm and a Saginaw pump.
That would be a good, reassonably priced setup.
I can explain how to do this, if you want.

George: I know in my heart that you are correct on this steering system !

My Benchseat 18 project needs everything; and I do mean EVERYTHING !

I am just trying to keep myself wthin a reasonable budget ~~~if possible ?

I am just trying to find a way to keep my costs down a bit before I wind-up plowing $20-25 K into this unusual custom benchseat 18 project !

I need a coplete new 350-400 HP Engine
Freshwater closed cooling system
Chevy bellhousing~~~
Marine manifolds, waterpump, motormounts ,
Marine 4 brl Carb,fuel pump, Starter & Alt .
Flame arrestor~~~
another better Volvo 270/280 outdrive
"T" trim Transom Shield Assy & hydraulic pump
new Solas propeller
Complete steering system
Complete throttle & shift system
Gas tank;
New benchseat tuck-and roll cushons.
Custom cockpit cover & carpet~
New Imron or Awlgrip paint job.
Trim tabs
Deck hardware & re-chroming
Gauges senders
Transom & stringer core work.
Donzi Decals~~~
Better Trailer
Fiberglass supplies etc .

And as you know all too well~~~
One new thing always leads to another~~~~

And then another~~~~

The complete list is almost endless ~~~~

My funds are not !

03-20-2011, 08:23 AM
Someone suggested to me once, that there're give away boats frequently on Craigslist and other places that you might aquire many of these things.
Just an idea.....