Yawl Self Steering

[Owly055]

     I've been intrigued by the various occasional bits I run across about balancing the mizzen in relation to the main on a Yawl in order to make them self steer without even using STT, but rather just lashing the tiller in the center.  The mizzen on a yawl seems frequently to be used more for direction control, and as a riding sail for at anchor, than for drive, which makes sense considering it's extreme stern location, and tiny size at around 15-20% of the total sail area.   The mizzen is far enough aft not to interfere with the main significantly, and it appears that many yawls are sloops where a mizzen was added aft of the rudder post, and no other significant sail plan changes have been made, or perhaps a slightly shorter mast or boom.   

     Anybody here ever experiment with self steering using sails only on a Yawl?  It would seem to me that with the rudder fixed, the extreme aft position of the mizzen, well aft of the CLR, would result in a significant moment opposing any change of direction as the wind loads increase and decrease as you fall off or round up.  Draw it up on a scrap of paper and it seems to work.

     Here is one of the few links on the web where someone has done this successfully.    The lack of links suggests to me not that it doesn't work, but that the yawl is not a popular rig these days.   http://navigatorjoel.blogspot.com/2013/05/the-incredible-self-steering-ellie.html

      Clearly a yawl rig precludes the use of the typical wind vane steering systems.  The only reasonable location for a vane would be on top of the mizzen, and while that would be possible, it would be a pain.    However the mizzen sheet might make a good sheet to tiller steering.  The mizzen on a yawl really is more of a large wind vane than a driving sail.

                                                 H.W.

[Owly055]

Here's a quote........... repeated in many places on the net:

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"The yawl was originally developed as a rig for commercial fishing boats, one good example of this being the Salcombe Yawl (a traditional small fishing boat built in Devon). In its heyday, the rig was particularly popular with single-handed sailors, such as circumnavigators Harry Pidgeon and Francis Chichester. This was due to the ability of a yawl to be trimmed to sail without rudder input. Modern self-steering and navigation aids have made this less important, and the yawl has generally fallen out of favor."

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Potential advantages of a yawl rig:

Self Steering
Balancing the helm
Tremendous maneuvering potential to the extent that yawls can actually be sailed backward
Storm Tactics.......... heaving to easily with all other canvas down, while maintaining the optimal 50 deg angle to the wind
Riding Sail
Additional drive potential using the mizzen and a mizzen staysail

It would be interesting to mount a short unstayed mizzen typical of a yawl near or even aft of the transom on a sloop or cutter.   Personally I believe that the reason the yawl rig has fallen from favor is that it doesn't really provide a great deal of drive due to the small size.   The extreme aft location means that a larger sail would negatively effect the helm balance.   This means that the mizzen on a yawl serves primarily for other purposes than drive.  As most sailboats are used for day or coastal sailing, the advantages of the yawl do not rate highly in most sailors estimation.   A ketch rig can utilize the mizzen to produce far more drive.   The goal of the ketch being to split large sail area into two more manageable sails.   The yawl doesn't do this, though with a mizzen staysail it can contribute significantly.   

I'm tempted to try a yawl conversion on a small sailboat just to see what I can accomplish with it.   There seems to be very little in the way of first party accounts in this area on the web, and almost nobody who has owned or sailed a yawl, that I've encountered seems to have really tried to harness it's real potential in terms of steering / balance, etc.  I also see no reason why one couldn't set up sheet to tiller steering from the mizzen sheet.


                                                          H.W.

[Owly055]

     Here are photos of Harry Pidgeon's Yawl Islander in which he made the worlds second round the world solo circumnavigation in 1921, and Francis Chichester's Yawl Gypsy Moth which set the world record solo circumnavigation 40 years later.   Note the extremely interesting mizzen on Gipsy Moth, clearly visible in the photo.  It appears to be sheeted from horizontal struts on a rotating mast, with a sheet to tiller steering line.  It also really does not qualify as a yawl in any real sense, as a yawl would normally have 15-20% of the total sail area.   I would term it a steering vane, not a mizzen.  The reefing system involving grommets and reefing lines is interesting and also very visible in this photo, and it appears to reef by raising the boom rather than lowering the gaff.  It's a gaff sail with a very short luff, almost triangular.   The islander by contrast has a huge mizzen sheeted to a sternsprit or boomkin.    They both are described as having used the yawl mizzen for self steering, though clearly this really is only true for Harry Pidgeon's boat.  Curiosity has driven me to order a copy of Harry's book,  Around The World Single-Handed, many copies of which are available inexpensively on Amazon.   

     Though it seems that few people are interested in this topic, I find it worth pursuing.  Note that I'm not quite sure how to insert photos, so I probably made a mess of things.   With that in mind, I've also inserted a couple of hyperlinks.

                                    H.W.

[img][file:///home/howard/GipsyMoth-chichester.jpg
http://www.thesundaytimes.co.uk/sto/news/uk_news/National/article392541.ece/img]
http://www.shippingwondersoftheworld.com/part31.html

[Owly055]

Trying again with attachments............

                             H.W.

[SeaHusky]

It would seem easy enough to use a dingy sail, perhaps an optimist rig, to experiment with, without having to make permanent alterations to your boat?

[Owly055]

I posted a photo of the Gypsy Moth III by accident instead of the Gypsy Moth IV.   Below..... If I can successfully add an attachment again is the Gypsy Moth IV.   I believe this photo is on Chichester's triumphant return from his record setting voyage.  Note that he has a much longer boat, and the mizzen is in the never never land such that it could be called a ketch or a yawl, and is quite large compared to the other boat.  Also note that he has a wind vane steering system independent of the mizzen that looks like an original Hasler Wind Vane System.  A classic photo of a very tired looking ship after a brutal passage.

                                              H.W.