[Public-List] Reversing the A-30

Sun Apr 3 15:30:39 PDT 2011

I remember the feeling of waiting for the diesel to 'spool up'.   For all
its faults, the old Atomic IV is good for power that right there when you
push the throttle.

I had a weird experience a couple of years ago with a client's boat that was
fitted with an electric auxiliary.  As we came up to the jetty there was no
reassuring rumble of an idling engine as guarantee that there'd be lots of
power in reverse to stop us.  As it turned out there was ample power but
with hardly a whirr or hum.

Just back from a day working on TOUCH WOOD.   This weekend in two days I got
her cast iron keel ground down to nearly smooth and a coat of anti-rust
paint on it; made and fitted two butt blocks and made a third; refastened
the skin planking to two of the floor timbers that are staying in the boat;
sanded the transom back down to beautiful rich red mahogany (it had been
painted) and sanded two of the three pieces the mast is in back down to
snowy sitka spruce (had a nostalgic moment when my sanding revealed the
white oak I'd inlaid to support the fastenings for the gooseneck track
twenty five odd years ago).

Went by SURPRISE to check her over... Removed her winter tarp and am
awaiting the rain which if it comes will comprise her spring cleaning...Came
home filthy but very very happy.

Gord #426 Surprise

On 03/04/11 4:54 PM, "Richard Mair" <ramair49 at gmail.com> wrote:

> As long as you are not doing this with a single cyl. diesel that takes 20
> seconds from full power in one direction to full power in the other. I think
> the flywheel was half the weight of the engine. Its gone now.
> Richard 609 Into The Blue
> 
> On Sun, Apr 3, 2011 at 11:41 AM, Gordon Laco <mainstay at csolve.net> wrote:
> 
>> Well I guess I asked for it.... Sorry this is so long but it's not easy to
>> describe briefly without access to diagrams
>> 
>> When backing up, the key is to only engage the transmission in short
>> bursts.
>> Remember that the boat will always try to weathercock her head down wind
>> and
>> make a plan that accommodates this.   If you have to make a turn while
>> reversing, don't rely on the rudder to be effective;  instead, use 'burps'
>> of power ahead (with lots of rudder) to shove the stern in the direction
>> you
>> need it to go.  Be aggressive with the throttle and picture a blast or jet
>> of water being directed by the rudder when doing this, but not so
>> aggressive
>> that you stop movement astern.
>> 
>> Where we keep SURPRISE a south wind, luckily rare here, can make getting
>> out
>> of our slip complicated because the usual backing out and turning involves
>> turning the stern away from the wind, the opposite to what the boat wants
>> to
>> do.  Since I know SURPRISE just won't want to turn her stern away from the
>> wind while backing out, I don't ask it of her.  We either turn the 'wrong'
>> way until she's done a 180 in reverse ( a complete U), then apply full
>> opposite rudder with full throttle to shove her head up so we can turn
>> again
>> and get out.... Or just back out.   The A30 will quite happily track
>> straight in reverse if she's backing upwind.  The natural tendency for the
>> bow to fall off helps in this case.   Once can avoid prop walk being a
>> problem by keeping the engine in neutral or just idling in reverse with
>> burps of reverse power keeping her moving.  If a sharper course adjustment
>> is needed, one can put the transmission in forward and give it a hard bash
>> instantly followed by going back into neutral before sternway is lost.  At
>> the first opportunity, we spin the boat in her length so that we can more
>> elegantly leave in forward.
>> 
>> To spin the boat in her length, a useful thing in tight quarters, one can
>> use the A30's weight and overhangs to help.  If at rest, get her moving
>> astern, but before she gets much way on, put the helm hard over and burp
>> sharply in reverse.  She'll stop, stunned, but her head will begin
>> swinging.
>> Get her moving astern again, but before much speed gets on her, do it
>> again.
>> The A30, like most traditional vessels, can use the heavy ends' tremendous
>> momentum which is developed once she starts a swinging motion.
>> 
>> This is easier if the boat has forward way on, such as for example coming
>> up
>> to a wharf that has a space between boats made fast alongside.  (in a car
>> we'd call it parallel parking)  Say we want to spin to port so as to slide
>> into the space, ending up with the bow facing the way back out...  approach
>> slowly... Start a turn in as if aiming for the centre of the space with
>> full
>> rudder then as the bow begins to spin to port put the transmission in
>> reverse and burp up to full power for a second.  The boat will stop
>> (stunned
>> is how I visualize it) but keep swinging to port... Let her start backing
>> then give her a burp ahead - remember the helm is still hard over causeing
>> the prop wash to shove the bow to port again.  She'll start moving forward
>> but before she gets much way on, go into reverse and stun her again.
>>  She'll
>> swing faster.  Do this a couple or a few times and the boat will be halted
>> with regard to way through the water, but will be swinging.  Once she has
>> nearly done her 180, give her a little reverse helm and slow ahead...
>> She'll
>> gently stop swinging and slowly slide forward into the space.
>> 
>> I appreciate this may be unclear when one is not watching it being done...
>> But I recommend people try it out in open water on a quiet day.
>> 
>> The reason we can do this better than most fin keeled yachts is because the
>> prop wash plays directly upon the rudder.  The cut out and the rudder
>> position in our boats is about perfect to direct the prop wash as a jet of
>> water shoving the stern forward or aft.  The A30's relatively great weight
>> imparts great momentum.... The prop wash will tend to spin the boat before
>> it starts it moving ahead or astern.
>> 
>> Back to reversing.... Imagine the boat doing 1.5 or 2 knots astern backing
>> down a channel.  The prop walk, the wind or whatever starts her tending off
>> course.  You know the rudder won't do anything so you krank the helm over
>> to
>> full in the direction you want the bow to swing... And burp a lot of power
>> just for a second, in forward.  The boat will slow... But so long as you
>> judge the amount of power correctly she won't stop, and you'll have shoved
>> the stern back into line and you can burp in reverse to keep her moving.
>> Obviously one can't do this too many times in a row or she will stop... But
>> that's good, because now you can spin her and finish the passage out in
>> forward.
>> 
>> In a cross wind, you'd be better off spinning as described above and then
>> motoring out normally because nothing will prevent the bow from falling
>> away
>> from the wind.
>> 
>> Sorry this is so Long and I hope it makes sense.
>> 
>> Gord #426 SURPRISE
>> 
>> 
>> On 03/04/11 8:18 AM, "Greg Bover" <gregbover at cbfisk.com> wrote:
>> 
>>> <<<<<<I've heard of that sort of thing.  My feeling is that full keeled
>>> yachts are
>>> 'less maneauvreable' than fin keeled yachts only when they are handled by
>>> sailors who aren't used to them.   Any full keeled yacht with a prop in
>> an
>>> aperture can be made to spin in its own length by use of rudder and
>> engine.
>>> Fin keeled yachts have made people lazy and forget how to handle their
>>> boats.
>>> Do I sound like I'm getting on a high horse?  I guess so! Sorry.
>>> Gord<<<<<<
>>> 
>>> All right, Gord, I'll admit it. I can't back up Linnet worth a damn. Care
>> to
>>> expand on your comment with some instruction?
>>> 
>>> Greg
>>> 
>>> Greg Bover
>>> Frances Fitch
>>> Linnet #114
>>> Gloucester
>>> 
>>> 
>>> Gregory R. Bover
>>> VP Operations, Project Manager
>>> C. B. Fisk, Inc
>>> 978 283 1909
>>> www.cbfisk.com
>>> 
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>> 
>> 
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