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Author Topic:   Hydraulic Steering for Twin Engines
peteinsf posted 07-17-2015 10:05 AM ET (US)   Profile for peteinsf   Send Email to peteinsf  
[Seeks] suggestions on how to decide if one needs two steering rams or one [steering ram] with a tie rod [to get hydraulic steering of twin engines]. My old setup with two standard rotation 200-HP motors clearly needed two [steering rams]. [That] set-up had one [steering ram] [and] was quite a workout for the helmsman.

My new setup will be counter rotation. Is a dual ram set-up [necessary]?


jimh posted 07-17-2015 11:39 AM ET (US)     Profile for jimh  Send Email to jimh     
Usually the manufacturer of the hydraulic steering actuator ram will give a specification for the maximum horsepower that can be used with that device. I'd follow their recommendations.

What is the total horsepower of the twin engines you are asking about?

contender posted 07-17-2015 05:02 PM ET (US)     Profile for contender  Send Email to contender     
I have seen both, two rams on two engines also one ram with a steering bar on two engines.
peteinsf posted 07-17-2015 07:06 PM ET (US)     Profile for peteinsf  Send Email to peteinsf     
400-HP total.
Hoosier posted 07-17-2015 08:59 PM ET (US)     Profile for Hoosier  Send Email to Hoosier     
I have two cylinders, one on each of my Yamaha F150. They are counter rotating. I think I have two cylinders because that's what the boat had before it was re-powered and they just re-used the parts, whether they were needed on not. It probably depends on the engine's weight and horsepower.
jimh posted 07-18-2015 05:25 PM ET (US)     Profile for jimh  Send Email to jimh     
Total horsepower = 400

OK, let's check the SeaStar website at seastar-outboard/#rec

As I read their table under OUTBOARD INSTALLATION RECOMENDATIONS, for twin-engine, counter-rotating, front-mounting, the recommended steering gear is:

600HP Max, 55 MPH Max
HC53xx Cylinder, HO60xx Tiebar

russellbailey posted 07-20-2015 09:38 AM ET (US)     Profile for russellbailey  Send Email to russellbailey     
My setup with counter-rotating twin Optimax 150s is consistent with what jimh posted - one cylinder and a tie bar - works fine.
peteinsf posted 07-20-2015 10:53 AM ET (US)     Profile for peteinsf  Send Email to peteinsf     
Cool, only one ram would save a lot on money.

The whaler drive had a side mounted ram cylinder with a linkage before, it looks to be a normal transom clearance wise so I may try a front ram and a linkage.


peteinsf posted 07-20-2015 01:01 PM ET (US)     Profile for peteinsf  Send Email to peteinsf     

I see some continuouswave articles hinting that Whaler Drive models need a side mounted ram. (Seastar HC5370)

jimh posted 07-21-2015 01:58 PM ET (US)     Profile for jimh  Send Email to jimh     
In the past I think it was fairly standard that a Boston Whaler boat ordered with a hydraulic steering system option would get a system with a side-mount cylinder. The two Boston Whaler boats from 1987 to 1990 that I have owned both had hydraulic steering with a side-mount cylinder; one was a standard notched transom and the other a Whaler Drive.

What article or articles did you find that seemed to warn off using a front-mount cylinder for steering with a Whaler Drive? Perhaps it is just a consideration for Whaler Drive and twin engines. On my single-engine Whaler Drive I don't foresee any problem with using a front-mount steering cylinder.

jimh posted 07-21-2015 02:01 PM ET (US)     Profile for jimh  Send Email to jimh     
You may already be aware of this, but I ought to mention: if you use dual side-mount cylinders the total system will return to a balanced system, and there won't be a problem using it with an auto pilot. A single side-mount system will be unbalanced, that is, the number of turns lock-to-lock is different in one direction compared to the other, because the volume of the two chambers in the actuator is apparently not quite the same.
peteinsf posted 07-22-2015 12:01 PM ET (US)     Profile for peteinsf  Send Email to peteinsf     
From "Reference, transoms and brackets"

"It might not be possible to fully tilt up the engines, particularly with the Whaler Drive option. For Whaler Drive installations, the factory recommended side mounted hydraulic steering."

jimh posted 07-25-2015 04:14 PM ET (US)     Profile for jimh  Send Email to jimh     
You must mean

Yes, under the heading "Twin Engines" that comment appears.

I recommend you check the dimensions of the center-mount steering actuator, the separation of the twin engines from centerline, and the dimensions of the Whaler Drive on your particular boat. The Whaler Drive size varies depending on the length of the boat. If you want a single cylinder center-mount for your twin engines on a Whaler Drive, you may find there is enough room depending on the several variables I mentioned above.

The problem with the Whaler Drive is probably the outer support ridges of the Whaler Drive (which conceal the big stainless steel support tubes that carry across from the original transom of the Whaler Drive transom). Those may interfere with the outboard ends of the center-mount actuator when the engine is tilted. I think some careful measurements should get to the real answer for your particular boat.

Tom W Clark posted 07-25-2015 09:46 PM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     
Pete -- Which of your boats are we talking about? A single cylinder will be fine for a pair 200 HP outboards. That old twin side-mount cylinder detail was terrible; the effort comes from the two cylinders fighting each other. It's a balanced system, but a lot of effort and v e r y slow steering response with about seven turns lock-to-lock when using a 2.4 cubic inch helm.
peteinsf posted 07-27-2015 11:51 AM ET (US)     Profile for peteinsf  Send Email to peteinsf     
Tom-- It's for the Outrage 25 Whaler Drive. The engines are twin 2007 E-TEC 2.-liter 200-HP with 350-hours on them--quiet, smoke free, big environmental and fuel cost upgrade from 1990 90-degree Evinrude 200-HP engines.
Tom W Clark posted 07-27-2015 12:00 PM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     
Just use a SeaStar HC5345 front mount cylinder with a 1.7 helm of your choice
peteinsf posted 08-22-2015 10:49 AM ET (US)     Profile for peteinsf  Send Email to peteinsf     
I checked the SeaStar installation manual for the front-mount ram model and it requires a 46-inch-wide transom well 6-inches below the tilt tube. I measured [the transom and splash well dimensions of a Boston Whaler OUTRAGE 25 Whaler Drive boat]. [The space available in the Whaler Drive of a Boston Whaler OUTRAGE 25 boat] appears to be about 43-1/2-inch wide at that measurement point. It looks like I'll need the side mounted ram after all.--Pete

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