Shape for trad ash tiller?

[Thorne]

I'm rigging my Chamberlain dory skiff by (mostly) following Gardener's plans for the sailing Whitehall as shown below.

My question: What dimensions to make the forend of the 4' tiller?

It looks like most of Gardener's tillers shown in the combined "Small Boats" books are horzontally flat in shape, unlike most tillers which seem to run with the large dimension vertically at the foreend.

For this rudder design, the rudder head is a single piece of 7/8" oak. The aft end of the tiller is split to fit around it and swivel up and down. The aft end is shown as 2 3/4" wide, but the fore end isn't shown in the drawings. Most of the "side elevation" drawings he has showing this type of tiller and rudder seem to show the fore end of the tiller as being very small.

I'm considering gluing up more ash underneath the forend of the tiller, then shaping it to the standard vertical form - but is this traditional? Or should I just leave it flat and about 2" wide by 7/8" thick? I also plan to put a bit of a downward curve into the tiller, as I'll be sailing from the floorboards a lot.

On another note, the rake on my boat's transom is much more than the Whitehall shown, so even though I followed the plans exactly, the blade of the rudder is dead vertical -- this is supposed to be good in tender sailing dinghies, right? The centerboard also drops straight down and is a bit longer than the one shown for the Whitehall.

Thanks!

http://www.luckhardt.com/MED_sailingwhitehallplans.jpg

[ 01-22-2006, 10:40 AM: Message edited by: Thorne ]

[Bruce Hooke]

I just made a new tiller for my father's 23' 3000' sailboat, so I've been paying attention to some of these matters recently. The thing I would focus on is getting a tiller that is easy to hold on to at the forward end. With this in mind, a tiller that is a LITTLE wider than it is deep makes sense, because that fits the shape of your hand, but 2" is WAY too wide. A tiller that is 7/8" wide and 3/4" deep at the forward end, would, I think, be about right (edited to add: actually, you could easily go smaller than that, but don't go so small that it is not comfortable to hold the tiller in a firm grip), and would be plenty strong enough. If this tiller is going to have strength problems it will be where it connects to the rudder, not out at the forward end (unless you end up with a lot of grain runout or similar issues). Make sure to round over the edges really well, to make it nice to hold onto.

The primary load on the tiller (unless you fall on it) is horizontal, so it makes sense that the tiller be wider than it is deep, especially at the forward end.

A vertical rudder is a good thing, BUT the problem you are going to have with the steeply raked transom is that as you turn the rudder it will tip up to the side by quite a bit. This is not such a good thing because that vertical angle is largely just adding drag.

[ 01-22-2006, 12:37 PM: Message edited by: Bruce Hooke ]

[JimConlin]

If the transom is raked aft, meaning that its top is aft of its bottom, and if the rudder pintles are roughly parallel to the transom. then won't the tiller's forward end will drop as it's moved off the centerline?

[DougWilde]

Yes, and that is a good thing, Jim.

Karl Stambaugh's plans for his Windward 15 shows a tiller that droops quite a bit. In the straight ahead position the fore end of the tiller is above the cockpit coaming. But as one turns the end dips down below the coaming, thus limiting it's arc.

This is a good thing because it prevents the rudder from going so far over that the pintels crash into the transom and ruin all those many coats of varnish over that beautiful mahogany. Besides, when the rudder is that far over it already has stalled.

Now if Karl knew that when he drew the plans he is one clever fellow. Otherwise he is a very lucky one.

Doug Wilde

[Thorne]

Thanks, that has all been very helpful.

Yes, the raked transom makes the tiller drop sharply, so I'll forgo the curving bit as that would result in smacked knuckles.

One advantage to the rudder plan as modified for this boat is that the blade hangs *straight down*, so the tip won't be tilting quite so much as a slanted rudder.

In these pix the rudder blade is swung up, as the darn dory is too heavy to easily prop it up and hang the rudder straight.

http://www.luckhardt.com/rudder-tiller1.jpg

http://www.luckhardt.com/rudder-tiller2.jpg

[ 01-23-2006, 01:00 AM: Message edited by: Thorne ]

[Wild Wassa]

Good looking boat Skipper. Cool pics. Do you have a Purple Heart fence? Wow.

Warren.

[Thorne]

Nah, the fence is stained "redwood" and the red color balance on my old Nikon is a bit off.

Glad you guys like the boat's looks -- most folks are a bit dismayed at how rough the exterior is, but I'm forcing myself to be patient and paint the hull last.

Anyway, I'm considering buying some brass straps / flat plates and laying them in on the sides of the tiller where it attaches to the head of the rudder -- as pointed out, that is where most of the stress will be. The two bolts will hold the plates in place.

[Tom Lathrop]

Unless you are extremely nimble, you will at some time fall on the tiller in a small boat. Some try to make the tiller and rudder head strong enough to take such a blow, but they usually fail unless they are very small themselves. I like a tiller that is strong at the rudderhead and gets progressively limber toward the end so that if/when you fall on it, it just bends and lives on.

As far as the shape and dimensions, there are many opinions. Just make it comfortable in your hand with a slight bulge at the end so your hand doesn't slip off. This will usually be round, rounded square or a bit wider than thick and 3/4 to 1" thick. The one in the photo needs a lot of shaving.

On larger boats, it needs to be bigger to take the stress of weather helm without bending too much and falling on it is not as likely anyway.

[Bruce Hooke]

I had not thought about the bulge to keep your hand from sliding off that Tom mentioned. That may well be a good idea. On the other side of the coin, I've done quite a bit of sailing on my father's boat, and that tiller does not have a bulge on the end and I've never felt like my hand was going to slide off. However, it could also be a case of not knowing what I am missing.

On a small boat like this I can also see it being more of an advantage to have such a bulge, because you are more likely to be sitting in front of the tiller and holding it behind you, in which position the bulge could provide a useful grip. On a larger boat you are more likely to be next to the tiller so the bulge might not matter as much...

[Thorne]

I might put a short hiking stick about 6-8" back from the end to let me go forward to the mast. But at this stage I'll sail it a bit before deciding on the tiller extension.

[ 01-23-2006, 05:36 PM: Message edited by: Thorne ]

[Todd Bradshaw]

I put a ball about the size of a billiard ball on the end of the last one I made. For some reason, I still have the original concept drawing, but never took any pictures of the boat that showed the tiller without it being inside it's Sunbrella cover....duh....

Anyway, it looked pretty much like this, although my real-life wood carving skills aren't quite up to my drawing skills, so the whole claw/ball/scales part wasn't quite this fancy on the finished product. The ball was a great place to rest your hand during casual sailing and is something I'd probably do again without hesitation.
http://www.imagestation.com/picture/sraid168/pfd711734577c8092629dc20b2f354a93/f42c3cd5.jpg

[Bruce Hooke]

Wow...pretty nice!

[Stephen Hutchins]

Todd,
Your gonna have to draw something for the dragon boat being designed on the other thread. -Nice work!

[Thorne]

I took a LONG look through all my Wooden Boat mags and building manuals, and from what I can see, fully 80% of the pictured boats under 18' have tillers that are vertical in cross-section.

Not sure if that is just the modern style, if the design has 'carried over' from larger boat tiller design, or if there is more functionality for that design compared to horizonal cross-section tillers.

I'll have to cut another ash tiller blank, as the end grain in the current one does run out in the worst places -- near both ends.

And with all that stress being concentrated at the rudder head, I'm considering gluing up two 7/8" layers of ash for the tiller. That would give me a beefier rudder head end, and the ability to shape the fore end more vertically if desired.

[Bruce Hooke]

The cross-section you are seeing in small boats may be a reflection of the fact that on a small boat the largest load on the tiller is likely to be someone falling on it, which is a vertical load. On a small boat it is pretty hard to generate the large amounts of side load under sail that would be typical of a larger boat.

A key point to keep in mind as well is where along the tiller you are talking about. Back near the rudder head most boats are going to have a tiller that is taller than it is wide, in part because this usually makes more sense in terms of the connection to the rudder or rudderpost. However, this clearly does not make sense on a boat like yours where the tiller wraps around the outside of the head of the rudder. On the other hand, at the forward end the cross section could easily be reversed (wider than it is tall) or simply fairly close to square to make for a good hand grip.

All of that said, I think you may be over-analyzing this. The connection between the tiller and the rudder appears to be pretty clearly defined on your boat. What you need to do now is just shape the forward end of the tiller to flow into the aft end cleanly while providing a good and comfortable place to hold on to it at the forward end. Grain runout is an issue, but whether the tiller is taller than it is wide or wider than it is tall at the forward end does not really matter that much as long as reasonably sturdy and nice to hold onto.

[Thorne]

Bruce -

You may be right, at the end of the day a tiller is just a tiller, after all. I'm not usually a fussy woodworker, more of a lazy one...

;-0 )

But I took a close look at the Gardner tiller/rudder connection, and the *entire* force of a turn comes onto those little sidestrips of the tiller on either side of the rudder head -- aprox. 7/8" thick x 1" wide x 6" long. The hole for the pivot bolt is drilled through the sidestrips about 1.5" from the aft end of the strips.

That's not a lot of wood to take any sort of jolt or pressure. I'm also not convinced that the forward bolt as shown in the plans does very much to keep the tiller from splitting -- sort of a tradeoff between: 1. protection against longwise splits, 2. weakening the tiller with an additional hole drilled through it horizontally.

The issue is further complicated by the fact that I've overbuilt the rudder by about a foot in length and 3 lbs of lead in weight. That may be changed if I find that the rudder drags too much or stalls out, as I can cut the additional length and weight off the bottom of the rudder blade.

But that's the joy of traditional designs, eh?

[ 01-24-2006, 11:46 AM: Message edited by: Thorne ]

[Bruce Hooke]

I think you are about right on the trade-off provided by the forward bolt. I think it does provide some real resistance to lengthwise splitting, so as a result the likely failure mode would now be cracking at the bolt on the "compression side" of the tiller (the side you are pulling towards). None-the-less, I think the net result of that bolt is a stronger tiller.

Given the increased size of the rudder, you do also have some reason to be concerned, and it seems to me that you might want to beaf up the aft end of the tiller a bit. A beefier tiller in that area might not be a bad idea. I like your idea of going thicker, becuase (for a tiller) it is already pretty wide in that area. Going thicker also means that each of those bolts removes less wood (on a percentage basis) than it would otherwise, so the negative impacts of the bolts are reduced.