Reimagining traditional dipping lug vessel (púcán)

I'm not sure what you mean by a lead keel shoe. Is the shoe part of the boat or part of the trailer?

 

Gybing is an activity that can stress people, and rigs, especially in strong winds, so was just mentioning that it isn't so bad with a balanced lug. Marconi and Bermudan are the same, Just that Marconi had cables holding up his tall aerials, so they looked similar, and were more familiar than 'Bermudan' in many areas. Keel shoe is on the keel bottom, the lowest position, sometimes made of wood - sacrificial to boring worms, can be lead for weight, or steel etc. for bottoming and scraping over shallows.

 

I have a lines drawing of an American version, known as a "Boston hooker" in my Chapelle book, American Small Sailing Craft.

I imagine it is very similar to the Irish one. I calculate that one with 20 ft LWL would have a beam of about 6.5 ft, an hull length of about 21.5 ft, and a draft of about 3.25 ft. It would displace 2 metric tons.

The bad news is that it has a fixed, full length keel. The good news is that this keel has a considerable amount of drag. This means that it is considerably deeper astern than at the bow. Tis could make it easier to trailer than its draft might suggest.

I don't think your stabilization fin idea would work. A major reason is the up word slope of the keel. This will create a lot of extra drag. Another reason is that the broaching is likely caused more by deep forefoot of the long keel than it is by anything else.

A better solution is to create the striking topsides of this vessel, but design a whole different underbody. This new underbody can swap the long keel with a shorter keel/centerboard arrangement with a skeg mounted rudder.

If the boat is made too much lighter, there can be problems with the dipping lug main. This weight is needed to maintain momentum while the lug is dipped. If this momentum is lost before the dip is completed, there can be lots of excitement aboard and entertainment ashore.

The dipping itself presents a few problems, especially with a lone sailor.
The first is how to get the yard into the other side of the mast in a reasonable amount of time. The other, is to get the tack of the sail on the other side

I can think of a solution to each of these problems.

For the yard, I can imagine 2 lines attached to the front end of the yard, one port and the other starboard. These lines can lead back to the cockpit. When a change in tacks is needed, the sheer is eased, as soon as the boat is pointed into the wind, and the windward one of these 2 lines is hauled to pull the front end of the yard behind the mast. It can the be eased, once the yard end is on the new leeward side.

The tack of this sail can be treated like a jib. It can have 2 tack lines, one port and one starboard, As the yard is being swung to the lee side of the mast, the windward tack line is eased and the leeward one is hauled, pulling the tack of the sail back to its original position but on the new leeward side.

After all of this is done, the clew of the jib would be hauled around to its new leeward position. Can you see see why you need this momentum?

A far less conventional approach can be used. This would be to split the lug at the mast. The fore edge of the aft portion can be laced to the mast. The aft edge of the forward portion can have 2 sheet lines and be treated like a jib. This way the yard does not have to be dipped, and the tack of this sail does not have to be shifted.

 

The Boston hooker is indeed very similar, the design was brought to Boston by Connemara people. There's still a strong connection. In 2014 mayor of Boston Marty Walsh thought it worth his while to put up election posters in Connemara (in the Irish language!) Mayor Walsh knows all about Connemara’s picturesque beauty https://www.bostonirish.com/travel/mayor-walsh-knows-all-about-connemara%E2%80%99s-picturesque-beauty

 

I'm not sure I explained my wing keel idea very well. I've marked it up on the drawing below. The fins would always be perpendicular to the water flow, a bit like a bilge keel but attached to the centre line rather than the bilges. I'm not sure what you mean by deep forefoot by the way, I would have thought it's a shallow forefoot.

 

Thanks for the fascinating insight into the dipping lug. I don't think I understand it fully, but I'm going to mock up a working model to try to get a better grasp.

I'm not that keen on your last idea. It sounds like a loosefooted gaff with a good side and a bad side. Or perhaps I've not understood. Thanks anyway for all your input!

 

By "forefoot", I mean the forward end of the full keel. In olden times, this was refereed to as the "gripe". Ever wonder where that word came from? When a boat started to broach, such was often referred to as "griping". The fins on the aft end of the keel you propose, may help to some extent. But I don't think they would do so to to the extent they earn their keep. And I don't think they are wide enough to hold the boat upright when the tide runs out.

As for the dipping lug.

The two sets of lines, I referred to in my previous post, attach to the lower end of the yard and the forward corner of the sail.

The ones that lead to the forward end of the yard are always on the same side of the mast as the yard is. They are simply hauled aft aft to pull the lower end of the yard behind the mast.

The ones that attach to the lower forward corner of the sail lead from turning block on the bow, behind the mast to the lower forward corner of the sail. When a tack is changed, the windward one is relieved and the leeward one is hauled. This pulls the corner of the sail behind the mast, on to the leeward side and then back to the bow.

The split lug will not behave like a loose footed gaff sail. The reason for this is because the yard extends a considerable distance forward of the mast and the top of the forward portion of the sail is attached to it. Not only that, but the tack of the forward portion of the sail is still attached to the bow. this gives much better control of the yard than can be had with a gaff, which will swing freely.

 

I was also thinking about some simmilar system to make the dipping lug a bit easier to tack to short handed crew. Do you think that the lower part of the yard could be pulled behind the mast without putting some slack in the halyard first? If so, the peak halyard would be needed to prevent the yard crashing down.

 

Hi, Igor.

When sailing, there are only three lines controlling a dipping lug.

Starting from the bow, we have the tack line. That holds the tack (the lower forward corner of the sail) to the bow.
Next, we have the halyard. This line raise and lowers the sail by raising and lowering the yard.
Finally, we have the sheet line. This controls the angle the sail is set at.

In order to swing the yard behind the mast, two of these three have to be slackened.

The two I would slacken are the tack line and the sheet line. Once these two are slackened, the yard is free to pitch up higher and higher until it is nearly vertical and its lower end can be pulled behind the mast.

Once that is done, it is relatively easy to slip the lower end of the yard onto the leeward side of the mast. Then, the tack line and the sheet line can be tightened.

In order for this all to work, the yard must hang from a pendant that is attached to loop that goes around the mast (the parallel). And this loop is attached to the halyard.

So, when the halyard is hauled, this loop is raised, and it raises the pendant which raises the yard. This pendant must be about 2 mast diameters long, if the mast is round, and 3 diameters long, if the mast is square.

This is to insure the yard has enough room to stand behind the mast.

It is theoretically possible to have all the controlling lines led after.

But there would be a lot of them.
2 for the port and starboard tack lines,
2 for the port and starboard yard dipping lines,
2 sheet lines, port and starboard, and
1 halyard.

Operating this sail would be similar to operating a Yankee, jib and staysail on a cutter.

 

Assuming we are talking about dipping lug on a unstayed mast I think it would require two halyards too- first halyard tied to the gunwale to act as a windward shroud and the second (lazy) which would belly out with the sail to prevent chafe.

 

I think that depends on where the centre of gravity is, doesn't it? No matter what the boat is made of, she should weigh the same so she sits at the proper waterline. If she's a traditional carvel built vessel, the hull itself could be 75% of the total weight so the centre of gravity will be quite high. On the other hand, if she's a lightweight monocoque construction (eg like grp or even the longitudinal glued double planking mentioned by Rumars above), the hull will weigh less and the wing keel will weigh more, significantly lowering the centre of gravity.

Conceivably, the c of g could even be in the wing keel itself. Remember this is a boat originally designed to carry cargo: A 20 ft version of this hull could displace around a ton and a half, whereas a Drascombe of similar length would be under a ton sailing weight. So if all the extra weight required to ballast the lightness of the monocoque is attached at the lowest point, the c of g could end up remarkably low.

Thank you to both you Shartpii2 and to Igor for the enlightening thoughts on dipping lug rigging, I'm intrigued but still processing them.