leeboards

[batory]

Is it a major technical challenge to convert a centerboard design to leeboards?

[JimD]

Tell the forum more about you boat. If you're talking about a 15 footer then nothing is a major technical challenge. smile.gif

[batory]

Originally posted by JimD:
Tell the forum more about you boat. If you're talking about a 15 footer then nothing is a major technical challenge. smile.gif Actually I was reading the Birdwatcher article in the latest WB issue and was just musing about leeboards and centerboards. The Birdwatcher has an offcenter "centerboard" to keep the central walkway open and I was thinking if it had leeboards that problem would be eliminated. It's not as if appearances play much of a role in the design.

[Tom Galyen]

I have leeboards on my 18th century replica "Jolly Boat, and have mused many times about replacing them with a center board for simplicities sake. Remember with leeboards every time you tack one must come up and one go down. It does complicate things.

Tom G.

[Levi]

My single leeboard on the port side has performed perfectly for 2 years in all situations and I wouldn't go back to that leaky centerboard box if you paid me. I put the leeboard down and it doesn't come back up until we beach or approach the rocky area near the docks. Kick-up rudder and kick-up board means no worries mates. Levi

[htom]

It depends on the hull shape.

Some hulls displace water away from the hull in ways that make "dirty" water flows near the hull into which a leeboard will not work well. Adding leeboards to these hulls does not work well. (greatly simplifying and probably misunderstanding and misrembering someone, perhaps Bolger.)

[tidmarsh]

Originally posted by batory:
Actually I was reading the Birdwatcher article in the latest WB issue and was just musing about leeboards and centerboards. The Birdwatcher has an offcenter "centerboard" to keep the central walkway open and I was thinking if it had leeboards that problem would be eliminated. It's not as if appearances play much of a role in the design.Remember that to work properly, a leeboard needs to be placed at the widest point on the hull so that it will be parallel to the waterflow as the boat moves forward. That may necessitate moving the center of effort of the sail rig fore or aft to make it balance.

For a more detailed discussion of the issues involved, see Jim Michalak's recent newsletter. (http://homepages.apci.net/~michalak/15jul04.htm)

[WindHawk]

Tom, couldn't one rig something along the lines of a tricycle front end, where you push on one side, and then the other goes up?

Forgive me, today is launch day, and I can't keep from thinking...

[rients]

Hi,

Coming from Holland where we have a large leeboard tradition with our round and flatbottom sailing vessels/yachts I can only say that the major challenge is not finding the right place and construction for your leeboard. We have a lot of constructions with a kind of "traveller" for the leeboard. You can adjust the place of the leeboard depending on windspeed, waves and sailing fullrigged or with some reefing.

I think the biggest challenge is to get the performance in windward situations. It isn't easy to sail with, it's diffucult to get hight and tacking gets a big new dimension. If not used in the right way and in the right manner you will get nowhere.

All the best, Rients

[ 08-20-2004, 11:33 AM: Message edited by: rients ]

[stepheno]

Does anyone know a source for larger size leeboard hardware,say for a 30' boat?
Or does anyone know how the larger leeboards of old were rigged; bolt, chain
or rope piviot point?
Thanks, steve

[John Bell]

It would be instructive for you to look at Jim Michalak's design catalog. He is a great proponent of single pivoting leeboards. Jim built one of the first Birdwatchers and used his experience with the boat to design more than a few Birdwatcher styled boats using his innovative leeboard. You might even find one of his designs appealing to accomplish similar aims as Bolger's BW.

[andrewdarius]

If you are looking for leeboards for larger craft, in "Sensible Cruising Designs", by Herreshoff, there are quite detailed drawings of the boards/hardware for one of the boats, I believe for Meadow Lark.

[Thorne]

As usual, hard to give an accurate response without knowing what specific boat / hull design and where/how it will be used.

Personally, I'd say that what the Dutch don't know about leeboards is hardly worth knowing -- was over there last summer and was astounded at the number of really different boats with leeboards.

Remember, if setting "foils" (which is what lee/center/daggerboards and rudders are) offcenter was truly effective, we'd see it all the time in boat design. Since we don't there is probably a number of good reasons to keep the foils either balanced (like twin keels and dual leeboards) or dead center like most centerboards / keels / rudders.

[Pernicious Atavist]

i use leebds on my 16' oystering skiff. they're a little more work, but when tacking, i just let down the lazy (weatherside) board, tack, then pull up the new lazy board. a little more work for a lot more pleasure!

now, when i laid out the boat, i placed my mast and board location appropriately, which you may not be able to do now. boards do need to be at the greatest beam.

as for hanging them, i have two xamples, somwhere, but can't find them right now. one is mechanical. the other, which will work on even mid-sized boats, especially yours, is merely a board on each side hangin from a rope.

it's not 'part' of the boat, but a seperate and removalble component. for mine, the board hangs from a rope tied to a thwart riser. the rope/board junction is at the rail, sometimes a little lower. the board gets moved fore and aft as needed, as mentioned above. very nice deal! to raise and lower the board, i attached a thinner line near the bottom. i passes over the rail aft of the sternmost tip of the board when it's in the all-up position. this line is knotted for a couple bd positions--all up, all down, and about midway. up is for when the bd is lazy, all down is when you need max bd, and midway is the normal position. i made the board a little oversized so i'd have extra in high winds, or when i get around to hanging a jib. the bd 'sheet,' if you will, passes through the rail into which i instlled a cleat--a notched piece of wood--that accomodates the line, but not the knot. pull the line away from the cleat, and allow the cleat to capture the knot. so easy! effective, fun, and best of all--i have an open boat without a cb.

hope this helps! if you need, email me and i'll take pics and send them.\

ed

[John Bell]

Remember, if setting "foils" (which is what lee/center/daggerboards and rudders are) offcenter was truly effective, we'd see it all the time in boat design. Since we don't there is probably a number of good reasons to keep the foils either balanced (like twin keels and dual leeboards) or dead center like most centerboards / keels / rudders.

In my experience, an offcenterboard or a single leeboard works just fine. My old Bolger Windsprint had a single offcenter daggerboard. I liked becuase it opened the best part of the boat for people. I never noticed a performance difference from tack to tack attributable to underwater assymetry. It's only if your are racing dissimilar craft that it might be noticeable. If you aren't concerned about racing in a mixed fleet, prefering instead to daysail, then I see no reason to require symmetry.