[PUP] Emergency tiller

[Scott E. Bulger]

Jim,  Thoughts below...

Dear Scott:

I'm sorry if I offended you but when we noted the following statement in
your
postings we recognized that something is wrong with your specific boat and
that you are incorrect in your presumption about the hull being unstable due
to the Maintenance Strakes.

[scott]  Fist, I'm not in the least bit offended, this is a valuable
discussion and the feedback of someone with your experience is of the utmost
value.  I am simply relating my experience so that others may benefit.  I am
also the first to admit that my experience level is that of Novice, I am
open to any and all feedback to any of my thoughts ideas or opinions (well,
perhaps except about catamarans).

You write:

The boat, with the fins off and pinned wanders all over the sea like a
sailor
on shore leave in the Roja district.

My 40' Nordhavn won't go 100 yards in a straight direction.  It never steers
a
set course without constant input from the autopilot or helm.  This is not a
function of the stabilizing fins, it does it with our without the fins
active.
I suspect the hull is unstable due to the "maintenance strakes" that give
you
the wonderful walk around in the engine room, a good compromise overall.

[scott]  Yes I did write that and nothing I have read in any of the
subsequent posts has changed my opinion.  As a matter of fact, as a result
of my post I have been contacted by several people that agree their boats
exhibit exactly the same trait that I described, that being that the boat
will only hold a heading for 10 or 20 seconds prior to needing a "bit" of
helm input.  This isn't a big deal, it's not a major defect in the boat, it
seems to me its simply the function of a complex shape moving through the
water with lots of appendages and dynamics going on.  To expect a N40 or any
trawler to steer like a sailboat would be crazy.    

I have seen problems associated with air in the steering system for years on
all of our models. On the first Nordhavn 46 we were completely dumbfounded
by
the symptoms of air and were temporary terrified that the fundamental design
of the 46 was flawed. Hand steering the boat was very disconcerting with a
severe lack of control. As described in yesterdays email the effect of air
in
the system will cause real control problems contrary to some of the opinions
offered by your friends.

[scott] I am sure air in the system would result in unsatisfactory
performance.  As I have said, I don't believe this is the case with my boat,
but Ill give it a look when I am in Stewart FL.

Well obviously the problem with the first 46 was diagnosed - the system bled
(it took numerous tries), the handling settled down and the boat (over 80
built) went on to develop a reputation for excellent handling and steering
qualities. You will note that the 46 has finer lines than does the 40 and
her
stern is very rounded at the waterline. The 40 has a much fuller stern
sections than the 46, carries her weight much better, steers just as well
down
swell, pitches less up swell and has a better ride at anchor. The 40 is
slightly less efficient (relatively) due to the fuller hull sections and
broader stern.

[scott]  I will make sure to keep the paragraph above and use it in my
advertisement for selling my 40 in a year or so!  It might help me win a
sale against a 46!  Thanks for the wonderful accolades of the 40, as I have
said, I love this boat!!!


I suggest that you take a close look at the steering system and make sure
you
have no air trapped within it. 

[scott]  I will do that in Stuart, it is just fine till then!

Contrary to other opinions I have seen posted -
having a consistent 30 lbs of air within the air reservoir does not mean
your
system if free of air - the pressure will help but you must remember that
the
systems operates at pressures in excess of 1,000 lbs and it's possible that
air is compressed within the system but still causing steering problems.
Bleed
it exactly per Hynautic's recommendation - we've tried to vary from those
directions and have found that the process cannot be varied. One more thing
-
I understand that after you bought the boat you added another autopilot
pump.
If the autopilot is mounted in such a way that any of the hoses or the pump
itself creates a high spot in the system - then air can get trapped and
normal
bleeding may not be enough to eliminate it.

[scott]  We followed the instructions EXACTLY.  I think the way we
determined we did not have residual air was to turn the wheel lock to lock.
There were two things we observed:  a.  There is absolutely a positive stop
when reaching the end of the ram travel.  B.  The number of revolutions from
lock to lock, and the relative position of the wheel remains constant.
Additionally, feedback put into the wheel is almost immediately registered
on the rudder position indicator of the dual autopilots.  However, the
advice is good and I'll check it out when I get a chance.  Oh, nothing is
higher then the ram, it's a foot or so above both pumps and associated
hoses.

Jim, thanks for participating in the list and taking an interest in my boat.
I think we have spent way more time discussing a nuance of the boat then is
necessary.  I was trying to be funny with my drunk sailor postings, it
wasn't intended to slight the boat or PAE.  Bad thing about email, its so
easy to misunderstand someones intention.  Again, thanks,


Scott Bulger, Alanui, N40II, Seattle WA
Currently in Costa Rica