Hydraulic steering 90 degree fitting question

[mjw930]

The prevailing wisdom installing hydraulic steering is to use a few 90 degree fittings as possible to help with steering effort (reduce restrictions). I’m just wondering what practical experience has show with those who have installed a lot of systems.

In my installation I don’t have any 90 degree fittings from the helm through the Seastar P/A unit so we are good here. In the rear I’m using bulkhead fittings to get through the deck positioned directly in front of the motor. From the fitting to the Seastar cylinder there are 2 90 degree fittings, one on the cylinder and one on the bulkhead fitting.

Here’s the question, if I use another 90 degree fitting on the inside of the bulkhead fitting to make a cleaner install am I adding enough additional restriction to make it matter. I’m on the fence and leaning on going straight just to maximize flow.

Opinions?

[JPEROG]

You will never feel the difference with the pump.

Joe

[mjw930]

I figured the pump would negate it but I’m sure it makes the pump work a bit harder. It’s probably insignificant considering the work it does to counter the motor torque.

However, your comment would indicate that without the pump there would be a noticeable increase in effort, is that a safe assumption?

[jpf091959]

I use 90 degree fittings purely for optics. I like having the hose close to the ram and coming through the boat.

[WillySteve]

I doubt your great great grandma could tell the difference.
The flow of molecules in a closed hydraulic system under pressure is unlike the flow of air!
If the restriction was a pinched hose or a small orifice to pass through then you'd see a diff.....in both the amount of effort required and delayed response!!!!

[mjw930]

Actually the issue with hydraulics is laminar flow vs. turbulent flow but point taken, it’s unlikely my installation will cause any significant increase in effort. Thanks.

[mjw930]

FYI, just in case anyone is interested, SeaStar and UFlex hoses are interchangeable, they use the same 3/8" compression fittings. This is significant if you are considering routing thru bulkhead fittings and aren't changing to a more generic AN style fitting as I have seen some do.

Here is why I consider this to be significant, the SeaStar bulkhead fitting uses a fairly cheap and basic brass pipe, cheap (ugly) washers and cast NPT to 3/8" compression fittings. OTOH, UFlex bulkhead fittings are Nickel Plated / Stainless and compatible with 3/8" compression hose fittings and they have the only 90 degree 3/8" compression fitting I have been able to find (SeaStar does not make one and the 3/8" compression fitting us unique to marine applications so there aren't a lot of generic fittings available).

Here are the SeaStar parts including their 90 degree fitting option:




Here's are the UFlex parts that accomplish the same thing without using NPT fittings, pipe sealant, etc...... The internals on the 90 degree fitting are radiused to minimize turbulence.



Here is a better photo of the kit with 90 degree's on both sides:



The part numbers are:

UFlex R7 - Bulkhead Fitting
UFlex MD 38 NI COMP FITT - 90 Compression Fitting

[FUJIMO]

If there is one 90 in the system, it would be the same as having more than one. True...or false?

[mjw930]

If there is one 90 in the system, it would be the same as having more than one. True...or false?

Each fitting introduces more turbulence so they are additive.

[Brad Zastrow]

in my opinion since the flow rate is very low on the steering system it will not make a difference. On fuel systems it is critical to use hi flow fittings.

[mjw930]

in my opinion since the flow rate is very low on the steering system it will not make a difference. On fuel systems it is critical to use hi flow fittings.

Interesting you say that since UFlex and Mercury engineers have both told me to minimize the number of 90 degree fittings in the steering systems. I imagine it's in response to people who make virtually every connection point a 90 degree fitting for esthetics, especially on larger boats with dual helms and multiple motors. They end up with multiple "T's" and other restriction points so my 2 bends are really insignificant.

[Brad Zastrow]

You asked what we thought, we told you. Every steering system I have seen has the hard 90 degree fittings on the helm and the rams.

[NeedOne]

in my opinion since the flow rate is very low on the steering system it will not make a difference. On fuel systems it is critical to use hi flow fittings.

This. Bernoulli's equation... There's like no flow so minor losses are negligible

[WILDMAN]

It won't make any difference no matter how many 90's you use, even without power assist. When I was trying to decide whether to use #8 JIC or #6 JIC lines on a twin, my hydraulic guy said that #6 can flow 30 gallons a minute. He said "do it really think it matters?" One Seastar cylinder hold 8-10 ounces.

[BUZZIN' DOZEN]

This is one of 2, 470's we have and has an

Arm Digging Force of

44,063–45,187 lb.

and I don't think there's a straight fitting on the machine