What am I doing wrong? Mobo steering?

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guyd

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bossingtonhall.co.uk
Ok....

I'd rather embarrass myself on here where no one knows who I am... ish.... than repeat the spectacle that was me the other day in my marina.

I've been mucking about in boats all my life. I'm 43 now. Started in little dinghys as a kid. Did seamanship level 2? Old school 5? Next one was instructor, anyway. Dads last boat was a Mitchel 23. My last boat was a Colvin 20 with a 12hp lister (for sale...hint) So the change to a semi displacement 24 footer shouldn't be any sort of shock? Nope. Looked like a total idiot.

It seems to just not respond to the tiller. Full whack either way and it just goes straight. Or traverses. Seems to sort of steer from the stern, i.e. Pushes her bum out, rather than turn amidships. Seems to take forever to respond to the tiller. At speed, it's fine, it's just around the marina.

Tried the steering one way, lots of throttle get it moving, whack it in reverse thing.... yeah, the local kids in the charter boats were all looking at me....

Doesn't look badly trimmed, fore/aft. New to me, so hardly any junk on board, and fuel tank at stern was 1/4 full but it's tiny at 100 odd litres



It's an arvor / quicksilver weekender 700 with a 150 vw lump.


What the hell am I doing wrong? Anyone sell balaclavas?
 
guyd said:
Ok....

I'd rather embarrass myself on here where no one knows who I am... ish.... than repeat the spectacle that was me the other day in my marina.

I've been mucking about in boats all my life. I'm 43 now. Started in little dinghys as a kid. Did seamanship level 2? Old school 5? Next one was instructor, anyway. Dads last boat was a Mitchel 23. My last boat was a Colvin 20 with a 12hp lister (for sale...hint) So the change to a semi displacement 24 footer shouldn't be any sort of shock? Nope. Looked like a total idiot.

It seems to just not respond to the tiller. Full whack either way and it just goes straight. Or traverses. Seems to sort of steer from the stern, i.e. Pushes her bum out, rather than turn amidships. Seems to take forever to respond to the tiller. At speed, it's fine, it's just around the marina.

Tried the steering one way, lots of throttle get it moving, whack it in reverse thing.... yeah, the local kids in the charter boats were all looking at me....

Doesn't look badly trimmed, fore/aft. New to me, so hardly any junk on board, and fuel tank at stern was 1/4 full but it's tiny at 100 odd litres



It's an arvor / quicksilver weekender 700 with a 150 vw lump.


What the hell am I doing wrong? Anyone sell balaclavas?
Click to expand...
First thing to check is if your rudder (I don't think Arvor is sterndrive) is moving when you turn the wheel (although you said tiller so you might be using the back up system). If not then overhaul the steering hydraulics or cable.
 
Re: What am I doing wrong? Probably Nothing.

Probably purely a matter of time and little else. All boats have their amusing little handling habits and always have one or two interesting ones in reserve just when you get a bit confident and presume having mastered the old girls quirks.
People watching does not help one jot. help one jot either. .
Had great trouble getting the hang of a easy to handle shaft driven boat after becoming an expert in mastering a boat with evil outdrives.Got so used to having to counter the wayward and contrary handling of a boat with all the weight hanging at one end.
Simply was not used to a boat staying where you put it and not trying to go in six directions at once..
On my first journey back to my home mooring,took at least 10 goes to get the thing alongside.
Am a bit better now,...but not much.
 
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Not at all familiar with your boat.

However the giveaway from your post is:
At speed, it's fine, it's just around the marina.


Which suggests:

1. You are going too slow and have insufficient flow over the rudder.
2. The rudder is incorrectly sized for the vessel.

Apologies if this is teaching egg sucking.
 
Surely any boat with a rudder or outdrive steers from the stern ( like a fork lift truck does !). I too try to do the right thing with forward/ reverse with my outdrive equipped boat to straighten it up when mooring in a crosswind , but it loves to go into alarm mode/ cut out the engine when it's needed the most; no power, no forward or reverse selected ( Thanks Volvo Penta EVC).
 
Tick over seems inordinately fast.... but then it's 150hp not 12....

Being an 'eau type hull, and quite common, i doubt the rudder is undersized. I will check movement, as it's hydraulic.i say tiller but it's from a wheel,( there's tiller backup), it's my dinghy days showing through.
 
Sounds like it would benefit from a bow thruster.
Boats with a single engine will always be trickier to handle around the marina than boats with twins, but it sounds as if a shaftdrive boat with a small rudder is trickier than most.
The steering effect from the rudder works best when there is plenty of water flowing over it. In the marina, there isn't much of that.
 
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As a rule boats over steer at speed and under steer at slow speed. But check the hardware first
 
guyd said:
Tick over seems inordinately fast.... but then it's 150hp not 12....

Being an 'eau type hull, and quite common, i doubt the rudder is undersized. I will check movement, as it's hydraulic.i say tiller but it's from a wheel,( there's tiller backup), it's my dinghy days showing through.
Click to expand...

I think most boats will be sluggish to respond to helm at engine tickover speeds (and low hull speed) as there is no (or little) prop wash over the rudder blade to substitute for low hull speed and create a turning reaction.
 
I think the OP has a real challenge.

Two engines and I teach slow speed manoeuvres with helm midships and almost always LEFT ALONE. One hand in your pocket (so you're not tempted to use one hand per throttle and end up confusing yourself with brain fade).

Then nudge it fwd and neutral etc. On lots of big boats, tick over is four knots. In calm conditions you spend a lot of time in neutral...

The op has come up against the basic rudder design problem in power boats. At high speeds it needs to be small and at low speeds vice versa.

Try full helm and using very short bursts of throttle to throw pulses of fast water past the rudder without actually making the boat jump forward too much? Find somewhere quiet and experiment is my best advice.
 
For the O/P I must have misunderstood ( judging by the posts of others) I thought you had a single screw vessel with a conventional rudder.

If that is the case it might be worth inspecting the rudder for integrity and also its lock to lock range which should be at least 35 degrees either side of midships. Reduced or inhibited range would not matter so much when making progress but would make a big difference in marginal flow conditions in the marina.

BTW, Investing in sophisticated controls will not overcome any fundamental hydrodynamic performance faults.
 
It is indeed a single screw, quite high pitch prop, with a single, middling size rudder imho. Certainly smaller than the Colvic old Skool type.

My colvic had quite large bilge keels, almost motor sailer size, which may account for its stability.
 
I've found my princess 30 kicks like a mule in reverse if on one engine for any reason (like running out of diesel maybe....:rolleyes:) to the point where reversing into a finger on the wrong side is almost impossible, I get it swinging round in forward to line up and give a bit of reverse and it goes straight back to where it was almost instantly (on shafts BTW not outdrives).
 
In the marina "slowly slowly catchee monkey" go out and play with it, see what the prop does for you leave the helm alone. In reverse the prop will take you left or right depending on it's hand, No quick bursts of power, just tick over, and if it goes too quick then in and out of gear. Finally do not let all the dockside experts get up your nose, nobody I know does it proper all the time.
 
Also it sounds like you are use to keel boats and this one has no keel and is a probably planning hull which means at slow speed its a bit like trying to push a wet bar of soap from the bottom up the bathroom mirror.. :) It's just going to take practice to work out how to coax her into the position you want.. Then you will have some wind or current and she will not listen anyway.. And yes I am still talking about the boat and not my wife.. :)
 
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