Height looks in the ballpark for a 115, but I suspect it could go higher without the prop venting on turns and at high trim angles- this depends on the prop you are going to be ending up with. Other posters have noted that as you lift the motor up the steering effort tends to reduce- and if the boat wants to pull left or right at speed you should be able to get steering wheel torque down to a minimum by playing with the trim and without having to trim excessively.
I set up a 115 Merc 4S last year with manual steering- the owner was complaining that steering effort was high at cruising speed and higher- which I verified. The steering effort could not be equalized in both directions by playing with the trim. This 115 had a trim tab on the cav plate, and with a tab adjustment the steering effort was the same in both directions when trimmed properly at cruising speed and above. I did have to show the owner how to trim for each speed to keep the steering wheel torque minimized. If the motor didn't run a trim tab on the cav plate- due to potential prop interference, then I would have added a pop riveted-on skeg tab. On this rig, I didn't find that the manual steering gear required excessive effort. I assume that your rig does not need a lot of force to turn the motor when it's not running- thus indicating a kinked steering cable.
Like it or not, if the factory/dealer doesn't have adequate info on what sort of engine height and prop selection combinations will work, then the owner has to "wing it" on set-up. In your case it sounds like T-Mac and others have given you tips on props that work, but engine height still is an issue. I really don't think you would need Seastar hydraulic steering on a 115- and you certainly should not need a full power steering system. In any event, a properly set-up and properly trimmed rig should not have the steering pulling to one side or the other at any planing speed.
Doug
|