Sunday, January 20, 2013

Catching Up on Some Comments

For quite a long time now I've been unable to up-load photos to my blog without going through the process of putting them on a picture hosting site and them using the url of each individual photo. With the combination of Christmas/New Year, and a lot of building work to be done, I am afraid that posting has fallen behind. This is all done in my own time, and at my own expense, and it sometimes must take second place to paying work!

The computer people here will roll their eyes, but I've finally discovered that the picture loading problem was caused by incompatibility between the Microsoft Internet Explorer I had been using and the Google Blogger program which I use for the blog. I've now changed to Google Chrome for my internet work, and all seems to be working fine.

So I'm going to start off by answering a few comments that have been left on some of my posts.

Mr.Lillistone,I've followed your blog for a while,Thank you for your time,energy ,and expertise,It is appreciated by many!!! I know you have built both Michalak's Mayfly and Redmond's Bluegill,I'm considering building either one and would like your professional opinion.Do you think the Mayfly leeboard and balanced lug sail plan could be used on the Bluegill ,if the sail is properly positioned over the leeboard,and leeboard is centered on beam?I would like the open cockpit the leeboard affords.Any info. Would be appreciated thanks in advance ! Jerry Fehn on Reality

The Bluegill we built, showing her centreboard case
Jerry's comment refers to a matter which has nagged at me for many decades. A centreboard is convenient to use and is to a large extent self-tending i.e. put it down and if you are too busy for detail work, just leave it down until it hits the bottom coming home. On the other hand, leeboards need to be handled from tack to tack because, as their name suggests, they only work when set on the leeward side of the boat.

A raised leeboard on a Dutch Yacht (taken from http://www.leeboards.com/)
That is me sailing my Bolger Nymph a long time ago. I had fitted her with leeboard for experimental purposes, but in this photo they are both raised as the boat is running downwind.
My understanding is that leeboards originated in China, along with such things as stern-mounted rudders, centreboards, and watertight bulkheads to name just a few Chinese nautical inventions/developments. Leeboard use has been widespread, but most people associate them with Dutch, German, and British sailing vessels.

This shows a typical lowed position for a leeboard.

Leeboards may appear untidy to some eyes, and to need handling from tack to tack, but they are highly efficient. Frequently the boards are angled away from the hull to allow a clean passage of water between the hull and the board so as to prevent excessive drag. This feature also means that as the boat heels, the board becomes more and more vertical - which is just the opposite of what happens with a centreboard or fixed keel. Not only does the board become more vertical, but it also works from the surface of the water, whereas the centreboard only works from where it exits the bottom of the boat. This has the additional benefit of allowing leeboards to operate effectively in a partially raised position in shallow water, and not extend below the bottom of the boat.

A Bolger Black Skimmer sailing with her board partially raised. The board is effective, but does not extend any deeper than the hull, if at all. (Photo from Woodenboat Magazine)
An overlooked plus with leeboards is that because they each operate operate on different sides of the boat (in their normal form anyway - more on that later) the sectional shape of the boards can be asymmetrical, allowing the board to lift the boat to windward at a reduced angle-of-attack in comparison with a board which has a symmetrical foil shape. The boards should have a flat face away from the boat and a cambered face towards the boat.


An Otter II with both of her leeboards raised while on her shallow water mooring. Note how the owner has the leeboards on the incorrect sides. The cambered section should face the hull, so in this case the starboard board is mounted on the port side, and the port board is mounted on the starboard side!
You may wonder why leeboards frequently have a tear-drop or triangular shape, with the widest part down low. This is because they are surface-piercing foils, and the inverted taper shape helps to reduce air-ingestion  on the low-pressure side of the board.

Despite the visual and actual clutter of the boards, they have some potent advantages in addition to the ones already mentioned: -

  • the interior of the boat is totally free of the intrusion of a centreboard case; and
  • the bottom of the boat is stronger without a centreboard slot; and
  • there is no centreboard slot to get jambed up with mud, stones, shell grit and sand - which therefore leads to the centreboard being jambed.
It is possible to mount the leeboard to one side of the boat only, but for that to be effective, the board must be prevented from bending away from the side of the hull when it is on the up-wind side. This can be done using a 'dagger leeboard' ( which I guess would be a 'weatherboard' on one tack) where a variety of methods are used to hold the board in place. Alternatively, you can have a pivoting 'lee board' as developed by Jim Michalak and others. In this case, the board is held parallel to the side of the boat by a pivot bolt and wooden guards and/or slots, but the board is free to pivot in the vertical plane. Although simple in concept, great care is required to ensure that all of the pivot locations and guard angles are absolutely correct.


Above two photos show the Michalak Mayfly 14 pivoting leeboard
Here is the finished boat
Note the completely unobstructed interior....
...the very simple raising and lowering gear...
...and the lower guard with the pivot bolt going through (the piece of unpainted wood is positioning piece on the trailer)
Now, to finally get to Jerry Fehn's question - Yes, it would be possible to mount a pivoting leeboard on Bluegill in place of the centreboard and case, but great care needs to be taken with the positioning of the board relative to the centre-of-area of the sail, and also with the geometry of the pivot point and the guards so that the board remains parallel with the centreline of the boat.

Having said all that, the first person who should be consulted would be Steve Redmond, the designer of Bluegill. As has been said many times in the past, no-one should alter the design of a boat without getting input from the original designer. This is not grandstanding at all - it is simply that the designer should have put a lot of thought into the design, and there may be elements there which are not obvious to the casual observer.

My recommendation would be to build something like Mayfly 14 if sailing is the most important aspect of operation. She sails superbly in my experience, and the shape of the hull is optimised for sailing whereas Bluegill's hull is a deliberate attempt to produce a hull that will row, sail, and operate as a planing powerboat.

Friday, January 4, 2013

Reality


I wrote this article many years ago. With the exception of the name of the main character, Mike Rowe (...Micro....), it is a true story.
Lying on the foredeck, Mike Rowe stared down the stem and contemplated the bow-wave of the small wooden boat. Behind him, and beyond the source of the regular “putoonk, putoonk, putoonk” emitted by the exhaust, Ken Foster sprawled in the stern sheets with his left arm laid out along the tiller. Ken’s look was distant, but relaxed. 

The boat these men were operating was of the simplest type. Built half-a-dozen decades earlier of inch-thick topside planking, with inch-and-a-half on the bottom, she carried the scars of her life as a fishing boat and hire vessel. Although she could not hide her age, she had done what the other boats in the harbour could not – she had aged gracefully.



Recent events had been kind to this beautiful boat.  

Ken had seen an entry in the classified section of the paper, offering some of a hire-boat fleet for sale. The business had changed hands and the owners were equipping themselves with a bunch of new, outboard-powered tinnies. Good business sense? Time would tell. 

At first sight, a lesser man than Ken could have been put off the deal. What paint remained was cracked and peeling, oil and fish scales lay in the bilge, and the motor emitted blue smoke and rusty water. The planking and framing showed evidence of “quick-and-dirty” running repairs, in which chopped-strand fiberglass mat starred prominently.  

Several months of hard labour had given Ken a renovated boat and a restored engine. New timber melded with old in a way which would have clashed in a more pretentious vessel, but which looked just right on this one. Brightwork was minimal, the paintwork was done in green and buff, and the engine displayed red paint, brushed bronze and drips of oil.  



Mike Rowe and his son had left the workshop early in order to go for a ride in Ken’s boat. They were planning the construction of a new putt-putt boat and intended to use a W.M. Olds & Sons 4-6hp four-stroke also. This was an ideal opportunity to sample the experience. For over a year, their engine had sat silently in the workshop, moving only when one of them put on a few drops of oil and then turned it over by hand to feel the compression. Imaginations had run gently wild. 

As Ken turned the crank-handle and his engine throbbed into life, they looked at each other in silent agreement. This was really good! Weather conditions were such that a trip around the harbour was more suitable that fighting the steep Moreton Bay chop whipped up by several days of 25 to 30 knot winds. The boat would have handled it without trouble, but that wasn’t the aim of the afternoon. 

They spent over an hour touring the yacht harbour, and in that time they made some interesting observations. At one point they stopped to examine a putt-putt of a similar size to Ken’s. This boat was lapstrake (clinker) but made of moulded fiberglass. She carried all of the standard add-ons which are thought necessary to make a “character” boat – bits of teak, brass bow-chocks and bollards, a heavily varnished rudder and tiller…  

Viewed amongst the surrounding plastic and alloy yachts, the ‘glass launch looked interesting and wholesome. But when Ken’s old thumper was tied-up near by, the new boat just looked silly. Despite having cost a tiny fraction of the price of the clinker production boat, the old and worn fishing boat won the looks contest hands-down. 



Our trio felt no envy as they toured lines of millionaire’s play boats, but the eyes of many observers followed them with interest. Which boat was delivering the most fun for the dollar? 

The bow-wave peeled off the side of the boat in a clean curl, swept down low amidships and rose to leave the transom in a gentle boil of prop wash and wake. Mike Rowe would have been happy to view this scene for hours, and he was captivated by the sense of speed. This speed seemed miraculous given the modest number of putts-per-minute, and the gentle rate at which the heavy flywheel was turning. 

Although Mike was a sailor by nature, he found the motion of this fine boat to be incredibly relaxing. The frequency of the engine sound was soothing, and the noise level low enough to allow easy conversation. Despite this, the occupants did little talking. Instead, they absorbed the sounds of the water passing the boat, felt the wind in their hair, and drifted within their own minds. 


Little wonder then, that these three people came ashore feeling relaxed and happy. Later, as they drove out of the car park, they saw a man who had glanced at their boat as he tied up his massive power cruiser. The man did not notice them this time, as they sat in the ute. He was concentrating on traffic while waiting for an opportunity to turn onto the main road. The big BMW accelerated past, and Mike Rowe observed that the man’s face looked fixed and preoccupied...