carbon fiber

[Joetech]

I'm thinking of making a new tiller for my Cat 22. The original tiller is cracked and I have fixed it several times. Since I have to haul it out soon I will have all winter it make a new one. I have access to a machine shop so tools are not a problem. At first I was thinking of making it like a knife blade handle with a piece of 1/8 aluminum between two pieces of oak or hickory. It seems that tillers are weakest in a vertical direction. I've seem numerous cracking or breaking in this direction by someone falling on the tiller or pressing down or simple fatigue in the laminated style.
Now I am exploring the idea of using a sandwich of carbon fiber in the middle. Does anyone have any experience with this? With an aluminum sandwich I would need to put mechanical fasteners and glue to bring it all together. With Carbon fiber, or kevlar I could use just an epoxy or polyester resin and just 'glue' it all together. Or at least I think so.

 

[Ross]

You need to study the stresses on the tiller and determine where you need to add the reinforcement. Remember that the center line is a neutral axis and could be hollow without taking away strength.

 

[larryw]

Axis, plane, stress, yakyakyak- carbon fibre is just plain phugly, but in a high-tech, industrial way, but I suppose it could be painted or something. I saw an ad once for a paint that mimicked a wood finish for spars and yards and things.

 

[Bill Roosa]

Carbon vs glass and technique

Carbon fiber is mostly for HIGH stress AND light weight. Probably could get away with glass and save some frustration and $$$.
Why not just wrap the wood tiller in fiberglass the cover it with gelcoat/bondo?
Or
use epoxy to glue your aluminum to the wood. A good roughing up with 80 grit paper will allow epoxy to stick mightly to aluminum. The wood would be decrotive in this case and just "along for the ride" so it is not like it has to handle any loads.

 

[tommays]

You can do pull-ups on a laminated wood tiller which is much stronger than any of the orginal solid ones

 

[philwsailz]

My common rescue for tired split laminated tillers is to first open all splits up and re-glue them. I use Franklin Tite-Bond II glue for this. Only medium clamping pressure is needed; I often just use clear packing tape, wrapped as tight as possible for a clamp along the split(s).

After the laminations are glued up. I go two steps further. The weak link in a laminated tiller is at the tiller stock, where the tiller is attached to the rudder. Most of the weakness is due to the cross drilling. I start out by going to the table saw, and with a fixture, I mill away about 1/4 inch of material on either sides of the tiller, for a distance of about 6-8 inches. The length is not critical. I then glue on solid wood material equal or slightly greater than the material thickness removed. I refer to these as glued-on cheek blocks in my image below.

After the cheeck blocks are fastened, sanded and faired to the rest of the old tiller, I mark and drill for the thru-bolts. Then I OVERDRILL the holes. Using a hardwood, teak or mahogany dowel, (I usually make my own using a die that was cut with the same drill bit I drilled the tiller with) I glue in two lengths of the dowel in the oversized bolt holes. At this point, I have modified the attachment end such that the laminations are tied together by the cheek block on the two sides, and the cheeks and laminations are tied together by the cross-dowels. This is procedure that is time intensive, but well worth it, as the result is a tiller that is much stronger at the typically weak mounting location.

After this is all dried and faired, I will usually use a filler stain on the tiller, and then apply a minimum of four coats of finish. Cetol is a favorite, but I am workig on one with varnish right now.

 

[Twice Around]

I've built several tillers...after you know what width you need (between the tangs on the tiller head, might as well measure the old one if it is correct) rip that width and then laminate alternate light & dark wood colors...I ripped mine to 1/4" thick on a table saw. After I had 7 or 8 pieces of wood, I soaked mine in the bathub to soften it and then laid around a form (some blocks of wood screwed to an old shelf board) for curvature. You could lay the old tiller on the shelf and then screw blocks down at the pressure points to simulate the old tiller, or design you own shape. I have used Gorilla Glue on my last two tillers since it uses water as a catalyst. I used maple & mahogany since that is what I had, but most are mahogany & ash I think. The maple is a little tough to sand. After you have a 2" square chunk of cured laminate, the shaping by hand is the tedious and fun part. I've used a chisel, belt sander, orbital, etc.

Sand to 220, and apply spar urethane, lightly sanding with 220 & tack cloth in between coats. Great winter project..I built one on the front porch of my old townhouse with a Workmate as a bench, or in the garage, etc..

Or you can go buy one at West Marine that is close to what you have now & save the aggravation. A carbon fiber tiller would be more complicated, but would look cool on a C-22

 

[RichH]

The easiest way to strengthen is to make the laminations in the area of the break THICKER, or add MORE laminations in the zone of the break.

Typically the laminations in a tiller are laid up 'horizontal'. Assuming that your intent to apply 'vertical' lamination in the 'tiller head end', ... could be a problem in weakening the horizontal laminations. Such tiller-head failures usually are because ONE lamination interface/face breaks, then the next, then the next .... so you might ALSO want to through-bolt the laminations (other than the very top /bottom laminations and only in close proximity to the tiller head) to strengthen the 'shear strength' of the laminations ... as well as add a few laminations where the tiller fits into the tiller head fitting.

 

[Ross]

Careful selection of wood species will make the largest difference. I have a 45 year old wheel barrow with white oak handles that I know have taken more strain than any tiller on a boat less than thirty feet. If you want it bent then steam it soft and bend it. Select wood with similar grain structure and gluing traits, white osk doesn't glue well with epoxy but is excellant with resorcinol. A study of the wood handbook will identify woods that are more shock resistant, or have greater strength in bending .

 

[RichH]

IUd stay away from 'solid' construction, as twisty grain is subject to 'checks' and 'splits'.

Attached is a sketch/illustration of through-bolt 'shear strengtheners' and added laminations.

 

[Ross]

IUd stay away from 'solid' construction, as twisty grain is subject to 'checks' and 'splits'.

Attached is a sketch/illustration of through-bolt 'shear strengtheners' and added laminations.

careful selection of the material requires a knowledge of the material. You must go to a sawmill and tell the people what you need and they will pick through a 500 board foot pile of wood to get the quality pieces you need. It won't happen at Home Depot.

 

[RichH]

"It won't happen at Home Depot" ...... ))))))

 

[Ross]

I needed 8- 5/4 x10 -8 feet long for some bookcases I am making They took an entire stack of lumber apart to find the best eight boards that I needed. Clear poplar 2.58 dollars per board foot. No charge for being picky. I can get clear african mahogany for 6.50 dollars / board foot at the same mill.

 

[tommays]

Call me crazy but i payed Defender the 68 dollars for a 1/4" mahogany and ash tiller with a very nice finish and can say after two seasons of racing it was up to the job

 

[Ross]

Call me crazy but i payed Defender the 68 dollars for a 1/4" mahogany and ash tiller with a very nice finish and can say after two seasons of racing it was up to the job

That is a very nice piece of work that you can't duplicate without a couple of thousand dollars worth of wood working machinery. I would need a bandsaw, thickness planer, router and several bits, belt sander, about a dozen clamps. I would need a bench set up for laying out the curve and a collection of blocks to clamp against.

 

[Steve Dion]

Tom:

I would totally agree with you. I am sure that you ended up with a superior product to what most sailors/woodworkers can produce.

The difference is many folks prefer the pride of doing it themselves.

My option is to do what you did. I believe that the tiller that you purchased was from H&L Marine in Rancho Domiquez, CA. They can make just about anything you need for your boat. As one time they made all of the teak for Catalina and several other mfgs. I had them make some drawer assemblies that I mounted under our settee.

 

[Joe]

I'm thinking of making a new tiller for my Cat 22. The original tiller is cracked and I have fixed it several times. Since I have to haul it out soon I will have all winter it make a new one. I have access to a machine shop so tools are not a problem. At first I was thinking of making it like a knife blade handle with a piece of 1/8 aluminum between two pieces of oak or hickory. It seems that tillers are weakest in a vertical direction. I've seem numerous cracking or breaking in this direction by someone falling on the tiller or pressing down or simple fatigue in the laminated style.
Now I am exploring the idea of using a sandwich of carbon fiber in the middle. Does anyone have any experience with this? With an aluminum sandwich I would need to put mechanical fasteners and glue to bring it all together. With Carbon fiber, or kevlar I could use just an epoxy or polyester resin and just 'glue' it all together. Or at least I think so.

Geez..... if you're just concerned about strength, a length of steel pipe with a handlebar grip would be plenty. It's better for the wooden tiller to break before the metal fitting that connects it to the rudder post.... cheaper too. On a catalina 27 a wooden, laminated replacement tiller runs around $80... the rudder post fitting is almost $300!...