Dennis,
While reusing a damaged sprocket isn't the best idea, the one thing I'd do
to prevent the chain override in the future is to get the bolt and nut out
of the chain and install a legit steering stop at the "quadrant" (really a
radial drive). As discussed by others, this would involve bolting an
upright heavy duty pin on the drive wheel that would hit against a wood
block on either side that was fiberglassed to a bulkhead. If this sounds
like too much work, the other option is to install a tether style rudder
stop that mounts a loop or padeye to the drive wheel and anchors a high
strength tether (usually a UHMWPE 12 strand like Amsteel or similar) to a
point on the hull or below deck, thus limiting travel. In tether rudder
stops, a shock absorbing snubber is installed in the system to prevent the
tether from ripping apart a bulkhead or below deck fitting.
Edson's Steering System Planning Guide found on their website can show you
several ways to install rudder stops. But relying on a bolt installed on
the steering chain to limit rudder travel has the potential of disabling the
entire steering system if pushed beyond the limit. You may also consider
chain replacement if the chain has been run over broken sprocket teeth for
an extended period of time.
Finally, one of the main reasons Rob recommended changing out the chain/wire
assembly for most steering systems is typically not due to excessive wear of
the chain on the sprockets, but instead as a result of metal fatigue due to
crevice corrosion between the link plates of the chain. Stainless does not
like to be deprived of oxygen and when it is, it performs very similarly to
mild steel (it rusts!) and the inside portion of a chain that you can't see
are the likely places for the corrosion to occur. Bottom line, I never like
using the terms "steering" and "failure" in the same sentence and I try to
do everything possible to make sure my steering system is up to snuff on my
35 year old boat.
Best of luck!
Chuck Gilchrest
S/V Half Magic
1983 35 Landfall
Padanaram, MA
From: CnC-List <cnc-list-boun...@cnc-list.com> On Behalf Of Russ & Melody
via CnC-List
Sent: Thursday, January 24, 2019 8:56 AM
To: cnc-list@cnc-list.com
Cc: Russ & Melody <russ...@telus.net>
Subject: Re: Stus-List Touche' steering system disassembly - issues of
concern discovered
Hi Dennis,
I will guess that the sprocket damage is as you surmise, chain stop bolt
riding past the limit. Notice chain link gouge in port side housing too when
it rode up on the sprocket. I expect it was an single event while backing
down and the person lost control of the wheel. There is enough momentum
there to put the wheel hard over in a second and cause the damage.
Your intuition is "bang on", reassemble without removing the sprocket.
Trying to get that sprocket off the axle is flirting with disaster.
Reassemble exactly as before, as the damaged teeth are not in the normally
loaded area anyhow.
Cheers, Russ
ex - Sweet 35 mk-1
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