Arwen's meanderings

Hi everyone and welcome to my new blog. My name is Steve and i am the lucky owner of a John Welsford designed 'navigator' named Arwen. I built her over three years with the help of my father, father-in-law and two children. She was launched in August 2007 at Queen Anne's battery marina in the barbican area of Plymouth. This blog is a record of our voyages together around SW England.
Arwen has a YouTube channel of her own. Search "plymouthwelshboy".

Thursday, 14 January 2016

Sail trimming...........the devil's dark art!

Over a few years I have written a few times about sailing Arwen and the intricacies of sailing a standing lugsail yawl, if that is what she is. I'm still unsure to be frank. Although I have been sailing several years now I still feel like a newbie and to all extents and purposes, I really am. I don't spend enough time doing the basics such as sailing onto and off moorings or onto or off anchor. The geographer in me is always yearning to see what is over the horizon, up the creek, in the next bay. This year however, I am determined to master the basics, because, mastering the basics will make me a better sailor, as one very wise member of the Dinghy Cruising Association, rather politely put it, recently. 

Previous 'Meanderings' about sail trimming with some excellent advice from John, Joel and others can be found here at these posts.

So where am I now? 
I have the basics of getting the sails up properly just about coming together

1. Loose snotter on the sprit boom when raising sail but make sure tack downhaul is attached 
2. Raise sail, making sure it is aft heel heavy, so that the yard is tied on in the lower quarter of the boom and parrel bead the tack bottom close to the mast without distorting the luff drop line
3. Raise sail fully until yard comes against top of mast at sheave point
4. Push sprit boom snotter mount higher up mast to just past first tack point line so it is angled
5. Tension tack downhaul and then set snotter to tension sail and get desired sail shape
6. Check boom not bouncing up and down
7. Up to 10 knots reaching and running ........tension mizzen, mainsail, jib last.
     Sheet Mizzen in hard but keep sail snotter looser for slightly baggy sail.
8. 10-15 knots ease mizzen and then main....check weather helm, reef over 15 knots
9. Reaching and running......jib, mainsail and then mizzen trimming order

Of curse, as always, someone is going to tell me I have got this on.........I probably have! So let me know please.

In the meantime, reading some posts on woodenboat forum posted by Todd Bradshaw, I have begun to improve the understanding that Joel and John so kindly took the time to share with me back along.

For a standing lug sail to work, and I think, stress THINK, that is how Arwen is rigged, then there needs to be imbalance! This is bought about by the halyard being tied onto the yard at a point far forward enough to make the yard aft end really quite heavy. Without doing this, the sail apparently rotates such that the boom, aft end of yard etc end up lying in the boat and the forward end of the yard just points upwards. I can't quite visualise this and I may have got it wrong, but the heavy aft tail end....that I do understand. 

Now to prevent rotation of the sail the tack downhaul** is tensioned to counter the imbalance via the sail tack corner. Considerable tension is applied to pull the luff straight and get the yard upwards to its designed angle. This same tensional force then runs down the sail leech, thus lifting up the boom's aft end off the thwarts and into its sailing position. Easing the downhaul tension just lowers the peak yard angle and boom tail, so don't! Similarly tying the yard halyard too far aft thus reducing the tail heaviness makes sail raising more easy but gives less luff and leech tension and as we have all been taught no doubt "a floppy sail is an unhappy sail"!!!! Moreover, sail shape fails, the yard bounces and so too does the sprit boom, and yes I have been experiencing quite a bit of that recently! 

So tack downhaul needs to pull and keep the tack down to generate luff tension and rotational forces to minimum and to stop the boom forcing itself forward of the mast, aided by snotter tension.

One the one hand I understand all this.......and then, five minutes later................


**i re recently inadvertently generated some debate on a small boat forum recently about the proper name for a tack downhaul. This is what I have heard people call it. It is how I call it but apparently it is wrong. The upshot of which is I have no idea what it's supposed to be called and so I will stick with tack downhaul ......sorry to any purists out there.


Alastair said...

Hi Steve,

If you want to learn to sail well, leave the motor at home. The boat will sail well on all points if it is set up right. When you haven't got it quite right the temptation is to start the engine. If you have no engine then you have to learn how to sail it properly.

It worked for me!

steve said...

Very true and wise words. I would need to change my launch site I think. Getting out of QAB in Sutton pool without a motor......well I'd have to be very brave as the exit from the south slip is about 4m wide between exceptionally expensive boats and on most prevailing winds would be a close haul situation
Not wide enough for may need to convert transom to sculling set up
But you are right motor.......too easy to give in

Alastair said...

I usually launch at Mountbatten or at Saltash. Both free, with free parking. Both drop you into (reasonably) open water.