Steering.

[Matt]

OK, I give in.

Originally posted by Johnny Boat Dude
No one runs twin side mounts on an outboard. Wing plates generally are not threaded like the O/B tiller arms and the Seastar setup has a lock nut on the bottom too. So its all just down to a smaller bolt at the end of the day and as i've said on many occasions just get yourself an ARP item as they're far far stronger than a standard stainless bolt.

[sterling]

Originally posted by Johnny Boat Dude
No one runs twin side mounts on an outboard. Wing plates generally are not threaded like the O/B tiller arms and the Seastar setup has a lock nut on the bottom too. So its all just down to a smaller bolt at the end of the day and as i've said on many occasions just get yourself an ARP item as they're far far stronger than a standard stainless bolt.

You are right about an ARP bolt ,its much stronger ,but its still a 3/8 fine thread .(9.5 mm)
Latham /mayfair and other brands use 5/8 fine thread( 16 mm) bolts to hook them to a wing plate.
In rough water I feel uncomfortable with that tiny little bolt.

sterling

[JamesM]

Originally posted by sterling
The seastar pro 2,4 has a 39,9 cc volume /rev
The capilano1250v has 22,8-55,7
I have a 1250v on my cat ,and I have the variable volume valve halfway ,I do not like the heavy steering feeling that you get when you set it at max volume .
So I think the seastar will do fine ,I have no idea how many turns you will get ,but you can measure the big volume side from a mayfair ram by filling it with oil and divide it through the pumpvolume.
I never tried to hook twin side rams to a seastar pro pump ,but I have no doubt it will work .

sterling

I've never seen a 2.4cu.in (39.3cc) pro helm and as far as I knew they were all 2.0cu.in (32.8cc). I've only ever seen it listed on the Hypro Marine website however its not on Seastars own site nor any other site I've ever looked at. So I've never been sure if this was a misprint or whether you could actualy get a 2.4 pro helm. Have you actually seen one in real life?

Also all the Latham/Marinie Machine type side ram setups I've seen have used the Capilano 1275V helm which is 2.7cu.in (44.2cc) to 5.4 cu.in. (88.4cc). When set on 2.7 with a marine machine ram its a fair few turns from lock to lock.

The standard sea star helm works with un-balanced rams but the pro helm is for balanced systems only.

[JamesM]

Originally posted by sterling
You are right about an ARP bolt ,its much stronger ,but its still a 3/8 fine thread .(9.5 mm)
Latham /mayfair and other brands use 5/8 fine thread( 16 mm) bolts to hook them to a wing plate.
In rough water I feel uncomfortable with that tiny little bolt.

sterling

I've heard lots of people say that rough water puts more strain on the steering but I've got cable and in the rough I can turn it pretty easily. However when its nice and flat and the motor is jacked right up, trimmed right out and the prop is surface piecing I have to jam my arm against the side to keep it going in a straight line and its almost impossible to turn left. This is in my opinion when the bolt is under the most stress. If in these conditions I had a hydraulic helm pump that ment I could easily turn the wheel to the left then I would be putting the steering bolt under a great degree of shear stress far more I would have thought than when bouncing through the rough on and off the throttle. I would be interested to hear other peoples opinions on this!!!

[BluFin]

Originally posted by scottyboy
Thats why i get paranoid about my steering and dont touch it!

Dont be, You cant keep running in straight lines

[Jon Fuller]

Originally posted by Johnny Boat Dude
I would be putting the steering bolt under a great degree of shear stress far more I would have thought than when bouncing through the rough on and off the throttle. I would be interested to hear other peoples opinions on this!!!

Sorry, I dissagree with that completely.

Certainly in a racing situation, where you're tearing along across a good chop (read 'rough), foot hard down, and the high mounted prop is continuously exiting and re-entering the water, allbeit for very short periods, ie, 'barking' as you run through/across it, the energy stored, then released in the flywheel effect of your rotating components, plus the actual power outputed, mean that especially with a high mounted drive, the snatch on and off off paddle wheel effect is massive, and a hydraulic system, which by nature doesn't allow any give (a cable system allows you to be a shock absorber to some degree), is very unforgiving indeed.

Do you think that you have enough mechanical advantage over your motor, via the steering to just turn hard on the wheel, and brake the bolt? I doubt it, but the constant slide hammer effect as described above has definitely loosened, and broken a few tiller bolts over the years, tho probably not the ARP bolts you speak of.

I'd personaly go with the 5/8" fellas anytime, as i'm sure would anyone who's had a steering system 'let go' at speed.

All just MHO

[BluFin]

Dont matter what type of system it at some point it will come too a single point. 5/8" is groovy but at the end of the day the key is to have the correct bolt, of the correct spec. Dont neglect it, maintain it or replace it regularly. Just coz it not corroded doesnt mean that it hasn't suffered deterioration of some sort.

[JamesM]

Originally posted by Jon Fuller
Sorry, I dissagree with that completely.

Dont be, I was just stating my observations from driving my boat and was open to comments.

My cable steering isn't the non feed back stuff and I've never noticed in the rough the wheel kicking around with enough force that if the wheel were fixed (non feedback) the bolt could break. Having said all that though I'm only doing 60 ish in the rough so it could be argued that for a 20 ish foot boat being used in that sort of application the big side ram systems are overkill and seastar with an ARP tiller bolt is more than adequate. I do agree however that on a 30 footer with twin motors doing 90 or more through a chop that Seastar Pro would probably not be upto the job.

The S and F boys run well over 100mph with surface piercing props using seastar pro and that must put massive sideways stress on the bolt!!!

[JamesM]

Originally posted by BluFin
Dont matter what type of system it at some point it will come too a single point. 5/8" is groovy but at the end of the day the key is to have the correct bolt, of the correct spec. Dont neglect it, maintain it or replace it regularly. Just coz it not corroded doesnt mean that it hasn't suffered deterioration of some sort.

[Jon Fuller]

Originally posted by Johnny Boat Dude
The S and F boys run well over 100mph with surface piercing props using seastar pro and that must put massive sideways stress on the bolt!!!

I refer back to my point, how often does a 100mph scream n fly fella run in the rough?

A smooth, continuous load aint gonna bust it.

Also, with the greatest respect, you should have half an hour in Ian Sirlings boat with him 'pushing-on' in the rough before you judge how much load it's possible to put on the steering.

jf

[JamesM]

I guess another factor would be what puts the most stress on the single pivot bolt. Steering the motor from the back with a wing plate setup or from the front with a tiller arm?

[JamesM]

Originally posted by Jon Fuller
Also, with the greatest respect, you should have half an hour in Ian Sirlings boat with him 'pushing-on' in the rough before you judge how much load it's possible to put on the steering.

jf

Yep fair comment!!!

[JamesM]

Does anybody know the shear strength of a 304 stainless bolt compared with a grade 8 high tensile steel bolt because the ARP is suposed to be stronger than a grade 8 HT bolt. Then with a bit of Pie R squared and what have you we could figure out the approximate strength of a 3/8 ARP and compare it with that of a 5/8 304 bolt. Could be interesting!!!

[Jon Fuller]

Originally posted by Johnny Boat Dude
Does anybody know the shear strength of a 304 stainless bolt compared with a grade 8 high tensile steel bolt because the ARP is suposed to be stronger than a grade 8 HT bolt. Then with a bit of Pie R squared and what have you we could figure out the approximate strength of a 3/8 ARP and compare it with that of a 5/8 304 bolt. Could be interesting!!!

remember the other end of the drag link has the exact same loads on it too

[Matt]

Think you need to factor elasticity as well as shear strength - but it's all too grey and in the distant past to remember properly.

[BluFin]

Originally posted by Johnny Boat Dude
I guess another factor would be what puts the most stress on the single pivot bolt. Steering the motor from the back with a wing plate setup or from the front with a tiller arm?

I have just sat here with a bit of paper, Drawing thrust lines, Drag,resultant foces, weight, moments, twisting & non twisting ect. Then intoduced boat movement for both Wing Plate & Tiller arm. Then end result is

I suspect a wing plate is better for no reason that I could justfy other than it has a greater distance to the steering pivot line.

Now I have a daft thought what would the effect be of an unbalanced cylinder mounted on the opposite side of the balanced effect ? ie differing surface area of the ram same hyd Px thereby one has greater effect than the other ??? If I explained that correctly ?????

[BluFin]

[JamesM]

Originally posted by Jon Fuller
remember the other end of the drag link has the exact same loads on it too

Other end of the drag link?

If thats what I think you mean then its not an issue with the Seastar!!!

[sterling]

Its not I do not like the seastar steering system ,its good enough for most aplications,I saw a couple years ago a broken bolt on a seastar pro ,the rig was a checkmate pulsare with a 300x merc
the boat was on dryland with a destroyed bottem ,thankfully nobody gets hurt.
Sinds then ,I am not so a seastar fan anymore .
Indeed a 3/8 unf high grade steel bolt is very strong,and wil not break easy(or never maybe )
a 5/8 bolt has 200 mm2 surface
a 3/8 only 70 mm2 surface
So at same quality its almost 3 times stronger
But if a high quality is used the 3/8 bolt wil flex more than a 5/8 and therefore wil be tired earlier ,and possible break .

sterling

[JamesM]

Originally posted by BluFin
I have just sat here with a bit of paper, Drawing thrust lines, Drag,resultant foces, weight, moments, twisting & non twisting ect. Then intoduced boat movement for both Wing Plate & Tiller arm. Then end result is

I suspect a wing plate is better for no reason that I could justfy other than it has a greater distance to the steering pivot line.

Now I have a daft thought what would the effect be of an unbalanced cylinder mounted on the opposite side of the balanced effect ? ie differing surface area of the ram same hyd Px thereby one has greater effect than the other ??? If I explained that correctly ?????

How much difference does it make that the ram is pushing and pulling from the side perpendicular to the direction that the motor is actually moving in?