Bow wanders at slow speed

[jamie langstone]

I have a searay 240 sundancer and at slow speed it just wanders all over the place. It can be a pain to try keep it in a straight line do other boats in its class do the same. Also do the 30ft boats with similar hulls do the same at slow speeds.

 

[neale]

It's a 'feature' of fast planing hulled boats at slow speeds. ��

It us often made worse by the person behind the wheel overcorrecting. Try to resist being too quick on the helm and you may find the boat wanders a little and then comes back. Less is more when trying to correct the wander.

 

[Rickard]

If you put down the trim tabs it will behave a little better

If you have a single prop outdrive a four blade prop will do good also

 

[Spi D]

My planing hull twin shaft 7.5 tonne mobo doesn't wander, but my previous 6 planing hull boats did, all to some extent.

Good advice to leave it alone as it will find it's average course with little correction. Adding a little to the speed normally helps - just stay away from speeds where fuel is used to keep the bow high. Either up to hull speed or planing at the lowest speed where it is on a stable plane, is my advice. And getting on plane is matter of full throttle until there, then back off.

 

[neale]

Sorry, meant to say 'fast planing hulled boats on sterndrives'

Tab advise is good too. Did this to good effect when I took my single engine Bayliner up the Thames and it did make a difference.

 

[Spi D]

Agreed. Sterndrives and outboards alike.
Duoprops wander less but still do, in my experience.

 

[jamie langstone]

Thanks for the info i will try the trim tap down and see if that helps.

 

[ontheplane]

Is this on a canal / river where you will never get over displacement speed, or in the harbour etc before heading off planing somewhere??

If you are on a canal or river, fit a rudder to the cavitation plate (I'm assuming Mercruiser not Volvo here)

When I was a kid my dad had the same problem with an outboard on a canal, max 4mph so no real steerage. He folded 2 sheets of aluminium into a L shape probably about an inch on the top and about 7 inches deep, about 2' long. Fit them to the cavitation plate - make sure they are absolutely parallel. This will transform the handling - BUT I wouldn't then want to travel above displacement speed as I have no idea what this would do to the handling other than probably make the whole boat totally unstable!!

If in harbour before going full speed then as written above, small corrections - barely perceptable, however another tip is that there is lag between the input and the boat responding, so what I do is like a "flick" - so if I need to correct slightly to stbd, I will turn the wheel slightly to stbd, then almost instantly turn back to the straight, the boat will turn half a second or so later, and you learn how much to do the wheel to get the effect you need. But when going straight, inputs are tiny, and more importantly very short time - if you wait until the boat starts to turn before straightening up, it will end up turning too far. This is why the boat wanders all over the shop.

So next time try it - go straight, turn the wheel very slight amount to the way you want to go, wait half a second and then turn it back to straight - and watch the overall effect. Slowly learn how much turn and how long to hold to get the adjustment you want.....

That way, the boat pretty much goes straight, however it does take some practice...

 

[Spi D]

If interested in that kind of device look up 'Ruddersafe'.

Presumably lifts when the speed gets above displacement..

 

[rafiki_]

This is quite normal for a single outdrive planing boat at low speed. As Neale says, the easiest way to manage this is to reduce your steering input, learn to anticipate which way she will head next and you will soon get used to it.

 

[Sea Ray]

I had a 240 Sundancer, great boat, loved it. So I know exactly what you mean. It's the nature of that type of boat at low speeds, you'll get the hang of it with practice. Other posters have said it all really, but if I was to repeat any of the advice given it would be "less is more" tweak the helm, and by tweak I mean a real tiny amount, and give the boat time to come round, other wise, like you have been you'll be over correcting and meandering, and it gets laborious as you've probably found out. If you get some wash, just ride it out and let the boat find its way, don't be in a hurry to steer (unless you have to !) and then correct course if need be.

 

[PCUK]

This is nothing new and a rudder on the outdrive will not be much help as it will simply increase the effect. The very simple answer to the problem with 100% success rate is to fit a small fixed skeg under the hull at the transom. This will act as a rudder and stabilise the straight line running of the hull. It will not affect the boat at high speed and as a bonus will protect the outdrive from damage. Made from 6mm epoxy coated mild steel plate it will cost peanuts to make and is easy to bolt through the hull with an internal stiffener.

 

[Momac]

With experience you learn to steer the boat more instinctively and the tendency to wander will become less tiresome.

 

[Joshmadson]

This is nothing new and a rudder on the outdrive will not be much help as it will simply increase the effect. The very simple answer to the problem with 100% success rate is to fit a small fixed skeg under the hull at the transom. This will act as a rudder and stabilise the straight line running of the hull. It will not affect the boat at high speed and as a bonus will protect the outdrive from damage. Made from 6mm epoxy coated mild steel plate it will cost peanuts to make and is easy to bolt through the hull with an internal stiffener.

This is nothing new and a rudder on the outdrive will not be much help as it will simply increase the effect. The very simple answer to the problem with 100% success rate is to fit a small fixed skeg under the hull at the transom. This will act as a rudder and stabilise the straight line running of the hull. It will not affect the boat at high speed and as a bonus will protect the outdrive from damage. Made from 6mm epoxy coated mild steel plate it will cost peanuts to make and is easy to bolt through the hull with an internal stiffener.

Hi Pcuk can I get some more information about this fixed Skegness you have mentioned as I would like to try it out

 

[ontheplane]

Hi Pcuk can I get some more information about this fixed Skegness you have mentioned as I would like to try it out

I don’t think this will work at higher speed - but will be ok at displacement speed. It could cause real problems at higher speeds

The rudder on the outdrive will work far better - but not at planing speeds it will make it very unstable then

 

[Bouba]

This is normal and especially noticeable when going slow in a river....Volvo solved this by putting a pair of counter rotating props on the same shaft (like a torpedo)

 

[Momac]

This is normal and especially noticeable when going slow in a river....Volvo solved this by putting a pair of counter rotating props on the same shaft (like a torpedo)

Duo-props do not solve the tendency to wander at river speed.

 

[Joshmadson]

This is nothing new and a rudder on the outdrive will not be much help as it will simply increase the effect. The very simple answer to the problem with 100% success rate is to fit a small fixed skeg under the hull at the transom. This will act as a rudder and stabilise the straight line running of the hull. It will not affect the boat at high speed and as a bonus will protect the outdrive from damage. Made from 6mm epoxy coated mild steel plate it will cost peanuts to make and is easy to bolt through the hull with an internal stiffener.

 

[oldgit]

I have a searay 240 sundancer and at slow speed it just wanders all over the place. It can be a pain to try keep it in a straight line do other boats in its class do the same. Also do the 30ft boats with similar hulls do the same at slow speeds.

My Princess 33 on outdrives would have difficulty holding a heading especially if a breeze was determined to push the head of the boat off elsewhere.
You eventually got used to it but could not leave the helm for any length of time( 30 seconds ) otherwise it was quite possible to discover you were now heading in a totally different direction from the desired one.
A previous owner had fitted a autopilot, now understood why.

Less of problem if you are just whizzing around but on a long reach constantly correcting to hold a course for an hour or two is bit knackering.

 

[PCUK]

Hello Josh, I've fitted one of these on all my previous boats, displacement and planing. In fact I'll shortly be making one for my latest rebuild! It transforms the straight line running at slow speeds especially when on autopilot. All it needs is a simple 6 or 8mm steel plate welded onto a mounting pad that bolts through the hull onto an internal backing plate of the same metal. If you can weld it'll take you about an hour to make and another hour to fit. If not then any fabricators will make it for a few quid or if you are anywhere near J27 M5 I'll make you one.