sailing downwind

[horburyd]

i need some advice as to how to improve my boat downwind performance. Is there any technical expert who can advise me . My boat tends to try and broach when sailing downwind unless constant rudder alterations are made

 

[TernVI]

Welcome to the forum.
You may get a range of answers including 'they all do that, sir!'.
Possibly you are over sheeting the sails and heeling the boat too much?
Are we talking about with a 'conventional' spinnaker?
What boat? What sails
Any particular wind/wave conditions?
In some conditions, some boats do need active helming downwind.
If you have a fair amount of sail up for the conditions, you may want to steer the boat to keep it fairly flat while avoiding the awkward waves etc.
But also heading too low is slow, so it can be a constant search for the best heading.
Some more information might help.

 

[horburyd]

the boat sails downwind if the mainsail is up and no genoe upto a force 6 more wind and 3 reefs and it is impossible to keep in a strainght line without broaching .

I was wondering whether the mast has been stepped to far forward?

Into the wind she is fantastic . She point very high

 

[TernVI]

With no foresail, the main will try to push the stern downwind and the bow up wind. Like a weathercock or wind vane.
If you're not racing, down wind in F6, just a little jib or a mostly rolled genoa is a good thing to try. It pulls the bow downwind.

 

[horburyd]

i feel the stern lifts very quickly when sailing downwind hence my belief that that the mast is to far forward but what you are saying is that i have the situation the wrong way around

 

[Ingwe]

i feel the stern lifts very quickly when sailing downwind hence my belief that that the mast is to far forward but what you are saying is that i have the situation the wrong way around

You want to move the sail area forward to increase stability downwind not back. Just think about where the centre of force of what is powering you forward is if you only have a mainsail up downwind - it is probably about 40% of the way out along the luff of the mainsail, so well out to one side of the boat and most masts are roughly above the keel so the force is acting to rotate the boat around your keel and hence you round up and broach the second you lose traction on the rudder, which you are bound to do as you are effectively fighting the sail plan with the rudder to keep the boat in a straight line.

If you just have a single foresail up it will still cause some rotation because again the power is just on one side of the boat, but because the centre of force is now in front of the centre of rotation of the boat, it is nothing like as much as when just under mainsail. The most stable solution deep downwind is to have roughly the same sail area on each side of the boat and for it to be as far forward as possible hence symmetrical spinnakers at the racy end of the spectrum and poled out twin headsails for long distance cruisers at the other.

 

[dunedin]

Knowing the type of boat would help get more informative answers.

But in any decent breeze, sailing downwind with genoa only and no mainsail is often very stable and relaxing (with no risk of a gybing boom to worry about)
PS. unfortunately the current fashion for tiny self tacking jibs on many modern boats removed this ideal cruising mode.

 

[horburyd]

That sounds a solution. The existing rig configuration is fraction-sloop rig. Hence the reason why the mast was step back as far as the setting on the plans. I therefore need to calculate are far forward the mast needs to be moved. Is there a formulae for arriving at this point? Or is it trail and error

 

[flaming]

Very difficult to comment fully without knowing the type of boat.

For example if we're talking about a 1970/80s IOR influenced boat I would shrug and say "sounds about right". But if we were talking about a modern shorthanded boat like a Sunfast 3200 etc, then something is badly wrong in the trim for this to happen.

In general, if your boat is a displacement design, then what the others have said above is correct - namely once you have control issues think of using less sail and bias it towards the front of the boat.
If however your boat is a planing design, then hold off reducing sail, head up a bit and get the boat on the plane where it will be a lot more stable (and a lot more fun) than running deep downwind.

You definitely should not need to move the mast. You risk upsetting the excellent upwind performance and you should be able to get what you want with different sail selection.

Please can you clarify the make and model of the boat?

 

[horburyd]

the boat is a steel vander stadt norman 40

 

[flaming]

the boat is a steel vander stadt norman 40

Then 100% you will have a much better time running in heavy weather if you use some jib. Either together with the main (ideally polled out on the opposite side) or on its own.

Main only is simply not a good choice for heavy downwind conditions in that boat.

 

[franksingleton]

We have a HR34.
In light winds, we use the spinnaker or, more often these days with advancing age, pole out the Genoa.
If it becomes difficult take in a reef.
If we know it is going to be very windy, we rig our inner forestay and the storm Jib. Then we sail with reefed Genoa boomed out and storm jib on the opposite side and no mainsail.
if it blows a real bomb, then storm jib only.

 

[RJJ]

Moving the mast is the last resort. Expensive and brings risk of unintended consequences

Changing the sailplan is the first resort. +1 for the headsail-only option.

 

[horburyd]

The other winter homework is discovering which canals and rivers are open to a sailing boat with a 2 metre draft. The canal de midi guarranttee 1.8 metres

I was thinking of the Rhine from Amsterdam to Austria

Any better suggestions?

 

[Laminar Flow]

The other winter homework is discovering which canals and rivers are open to a sailing boat with a 2 metre draft. The canal de midi guarranttee 1.8 metres

I was thinking of the Rhine from Amsterdam to Austria

Any better suggestions?

As in upriver from Amsterdam? You will find it hard going where the Rhine flows through the "mountains", especially in conditions where you have enough water to float a boat with 2m draft and particularly as you will not likely be able to benefit from a slower current near shore. I have done this trip in a 50' twin screw, lifting keel boat and barely made it. Even the very elderly pedestrians were outracing us alongshore.

I seriously doubt there is any chance you would make it through the Midi; even the 1.8m is highly aspirational.

 

[horburyd]

So it is the Norwegian Fjords next year

 

[Pete7]

As in upriver from Amsterdam? You will find it hard going where the Rhine flows through the "mountains", especially in conditions where you have enough water to float a boat with 2m draft and particularly as you will not likely be able to benefit from a slower current near shore. I have done this trip in a 50' twin screw, lifting keel boat and barely made it. Even the very elderly pedestrians were outracing us alongshore.

I seriously doubt there is any chance you would make it through the Midi; even the 1.8m is highly aspirational.

Impossible more like. Horburyd, worth watching the series by yacht Ruby Rose on You Tube. They have a lifting keel Southerly 38 and struggled at times. We might get through with a draft of 1.1m. Don't even think you will make it through the main French canals from the Channel to the Med with 2m.

Caledonian canal is a possibility, or even the Swedish mast up canal called Gota. Ran Sailing on YT are doing it at the moment in a Najad 44.

Ok, back to racey fast boat threads.

 

[TNLI]

i need some advice as to how to improve my boat downwind performance. Is there any technical expert who can advise me . My boat tends to try and broach when sailing downwind unless constant rudder alterations are made

The obvious solution is headsail only, but if the problem relates to use of an autopilot, then nothing seems to beat a Hydrovane, although some of the more powerful electric or hydraulic pilots set on high gain are OK.

If that fails, then try slowing down a tad, as the only other option is moving the mast closer to the bow, or selling the boat for a long keel job. Last thought, try trailing a warp in heavy weather!