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Advice on drilling a rudder blade and tiller arm? #109247
06/08/07 05:53 PM
06/08/07 05:53 PM
Joined: Sep 2002
Posts: 23
Utah, USA
AlphaGJohn Offline OP
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AlphaGJohn  Offline OP
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Joined: Sep 2002
Posts: 23
Utah, USA
Hi Folks,

Having broken a rudder, I ordered a new one through my local shop--it came undrilled (not what I'd expected). Any suggestions for drilling the while plastic (other than keeping the drill speed on the slow side so it doesn't burn the hole)?

What's particularly annoying is that the replacement isn't exactly the same size as the original blade (it's just slightly smaller fore & aft). I don't want the location of the bolt hole for the upper casting to be too close to the aft/top corner--that's where it broke last time. So, should I split the difference or put all the difference on the forward side?

Also, anyone have any bright ideas for clamping the thing to the drill-press table so that the holes are perpendicular to the top of the blade? (It's not exactly a nice flat shape....)

(Should I have ordered another part number to get one pre-drilled or is there some reason I haven't thought of for it to be a drill-your-own exercise?)

I'm also having to drill holes for the upper casting to connect to the tiller arm, but my thought was to just get the rudder drilled and the upper casting attached to it so I can fine-tune the angle of the tiller arm so it matches the other side (using the crossbar to judge correct angle).

Any thoughts and suggestions appreciated!


John Craig Utah County, Utah '95 Hobie Wave
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Re: Advice on drilling a rudder blade and tiller arm? [Re: AlphaGJohn] #109248
06/14/07 05:47 PM
06/14/07 05:47 PM
Joined: Jun 2001
Posts: 1,252
California
mmiller Offline
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mmiller  Offline
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California
Well, since we have used the same mold (Steel) for decades... hard to see where it would be of a different size, but maybe a slight difference due to trimming? It was purchased from Hobie right?

We only stock un-drilled blades as there are so many different uses of the same blade.

Simple solution? Take the opposite blade off andf use it as a drill guide. You can also download a little paper tenplate from out support area: http://www.hobiecat.com/support/pdfs/rudderdrill.pdf

These blades are Nylon and drill easily.


Hobie Cat Forums
Matt Miller
Hobie Cat Company
Re: Advice on drilling a rudder blade and tiller a [Re: AlphaGJohn] #109249
06/20/07 06:02 AM
06/20/07 06:02 AM
Joined: Sep 2002
Posts: 23
Utah, USA
AlphaGJohn Offline OP
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AlphaGJohn  Offline OP
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Joined: Sep 2002
Posts: 23
Utah, USA
I don't know how to account for the difference in size of the rudder blades, but it's more than trimming would suggest (the old one is 1/4 to 3/8" wider fore and aft). The boat is second hand and I think the guy we got it from isn't the original owner either so I don't know if the prior set of rudders were stock Hobie parts (the ones that came on it were black, but not fiberglass or carbon fiber or anything that looks like what is available in the Hobie catalog at the moment). So maybe the "originals" were from some 3rd party supplier.

As I looked at it, the break occurred at the top, aft corner of the broken rudder and it broke right through the hole for the tiller arm/upper casting's bolt. This hole didn't look entirely straight to me (that is perpendicular to the blade)--that might account for why that one's always been hard to lock down (the upper casting tended to hit the lower casting--especially when loaded by a substantial wind). I think all those times of trying to lock it down with the upper casting banging on the lower one perhaps led to the break in the first place (it'd just had more stress than it should have with the bolt pulling against the hole in ways it shouldn't have).

So, I wasn't sure how to line things up (and since I only had half a bolt hole to judge by, I'm not sure if the hole really was untrue). In any case, I ultimately just positioned things so that the forward edge of the rubber would line up with the prior setup as best I could tell. (Unfortunately, I didn't see the info on the drilling template until after I'd already done the work.) I used a spring-actuated center punch to mark where I wanted to drill (using the prior holes as a guide). I set the drill speed at around 700 rpm and it drilled very nicely with a regular twist bit. The top part of the rudder is flat and holding that down tight to the drill press table worked well; I didn't bother trying to clamp it. The fit between the upper casting and the lower one turned out to be very good with the holes I drilled (although I haven't had a chance to test it under wind load yet).

Trying to drill the tiller arm turned out to be a much larger challenge (I'm guessing there's no published template for this; I sure didn't see anything when I looked just now--which just goes to prove that the really dumb thing in the whole situation was allowing the tiller arm and upper casting to get washed off the boat after the rudder blade got broken!). I bolted the upper and lower castings to the newly-drilled rudder and mounted it on the boat so I could use the tiller cross-bar to judge the appropriate positioning of the tiller arm in the socket of the upper casting. (Rotating the arm slightly in its socket makes a big difference in the side-to-side positioning of the forward end of the tiller arm.) The cross-bar turned out to be completely inadequate for judging the correct angle (the cross bar's flexible ends made it hard to tell if everything was even). Eventually, I found a thin piece of wood about 2 1/2" wide that I laid along the flat part of the outside edge of the upper casting so that it lay against the upper casting and passed just under the forward end of the tiller bar (the tiller arm angles out from the upper casting somewhat so the forward end is quite a bit outboard of the upper casting). Using the undamaged rudder and casting on the other side of the boat to guide me to the correct amount of outboard tilt, I got the arm rotated in the socket so that the angles between the upper casting on the new side and the older, undamaged side were the same. I tried to use the center-punch to mark the holes (this wouldn't work well with a regular pound-it-with-a-hammer style punch but with this spring-actuated gizmo, you can hold the business end against the item you'll drill and just pull back on the spring end with your other hand and let it go). Unfortunately, I didn't get all three holes quite aligned with each other. Another time, I think I'd mark all three holes (perhaps with a felt-tip pen), drill the one on the drill press, and then rivet that one in place. At that point, I'd drill the others with a hand drill using the upper casting's holes as a guide for the drill bit. As it was, I ended up having to enlarge one of the holes slightly so that I could get the rivets into all three holes. It seems to still be good and tight so I trust that won't become a weak spot (the socket in the upper casting holds the arm quite firmly so the rivets' main job seems to be holding the arm in the socket.)

My cross bar is the old kind that has a spring loaded stud on the end of the cross bar that mates to the tiller arm by popping out of a hole in the bottom of the arm when the cross bar end is pushed all the way into the till arm. After laboriously fighting with the holes to get the arm rotated at the proper angle in the casting's socket, I messed up the hole in the bottom of the forward end for the cross bar's stud--which should have been a much simpler job. So I now have this little pinch-your-skin-sized gap between the cross bar's rubber corner bend and the end of the tiller arm--crumb! I haven't been able to figure out anything that is likely to resolve that without a major effort. It hasn't been wet tested yet either, but I hope it'll prove to be a minor issue.

In any case, I'd like to suggest to our Hobie rep that you folks consider offering drilling of the parts as an extra-cost option. Given that you presumably have jigs to make this easier, it'd definitely be worth it for those of us who have to figure it out as best we can. I'm sure there are plenty of handier folks than I who would have done a better job of this on their first try, but I'm equally sure there are lots of folks who would be pretty flumoxed--or, perhaps worse still, would mess things up worse than I did and end up pretty dissatisfied with the results. Why not have a "subassembly service" so we could buy an upper casting, a tiller arm, and the assembly work (so we'd receive the casting with the tiller arm already mated to it), for instance?

In any case, I can't wait to get back on the water. (We're in the midst of a dry vacation this year...sigh.)

Last edited by AlphaGJohn; 06/20/07 06:08 AM.
Re: Advice on drilling a rudder blade and tiller a [Re: AlphaGJohn] #109250
06/26/07 02:56 PM
06/26/07 02:56 PM
Joined: Jun 2001
Posts: 1,252
California
mmiller Offline
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mmiller  Offline
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Joined: Jun 2001
Posts: 1,252
California
Quote
I'd like to suggest to our Hobie rep that you folks consider offering drilling of the parts as an extra-cost option... Why not have a "subassembly service" so we could buy an upper casting, a tiller arm, and the assembly work


This is what a dealer is best at. Contact an authorized dealer for this kind of thing (drilling etc).


Hobie Cat Forums
Matt Miller
Hobie Cat Company
Re: Advice on drilling a rudder blade and tiller a [Re: mmiller] #109251
06/29/07 10:44 AM
06/29/07 10:44 AM
Joined: Sep 2002
Posts: 23
Utah, USA
AlphaGJohn Offline OP
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AlphaGJohn  Offline OP
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Joined: Sep 2002
Posts: 23
Utah, USA
Hmmm. I'm not sure you want to give the responsibility for that job to dealers. The authorized dealer (a long-time Hobie shop), I bought the parts from, didn't offer to do the drilling and since I can't imagine they'd have the right jigs to make the drilling simple, that seems odd advice. In the best case, you're leaving to your dealers to ensure the quality of the job. Doing so is inevitably going to mean inconsistent results for your customers. (I also happen to know that our Hobie dealer's old hand with repairs and so on has just left the shop to take another job. I doubt if the new guy--a monohull afficianado who admitted to us he knew nothing about Hobies--would have any idea what to do.)

As an example of the kind of inconsistency that is bound to result from dealer to dealer, Hobie's site says a dealer can order parts and have them shipped right to the customer if you wish. When I asked our dealer about this, they assured me that Hobie wouldn't do that. Since it wasn't a big deal, I didn't push it. So, how is physical work like drilling going to be done consistently (a skilled job which would typically be done with specialized tooling) when some dealers aren't even aware of company policies?

I don't mean to be snippy, but saying "This is what a dealer is best at" is just odd-sounding. If that's so, why don't they get raw parts for the boats they purchase for sale? I think it really is worth passing along the suggestion rather than telling me to rely on someone who has no quality control, doesn't have the right tooling, and may or may not have the expertise to do the job right.


John Craig Utah County, Utah '95 Hobie Wave
Re: Advice on drilling a rudder blade and tiller a [Re: AlphaGJohn] #109252
06/29/07 11:14 PM
06/29/07 11:14 PM
Joined: Jun 2001
Posts: 1,252
California
mmiller Offline
veteran
mmiller  Offline
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Joined: Jun 2001
Posts: 1,252
California
My advise will most commonly be to refer customers to dealers. That is our chain of service. There is a simple template that can be used for the drilling and I can teach the new guy about that if needed. That way he can also help the next guy.


Hobie Cat Forums
Matt Miller
Hobie Cat Company

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