PS Britannia high and dry

[Tony Mattson]

I have posted another photo to Britannia's album.

It shows Britannia high and dry on Flat Rock, which she struck while
taking a picnic party down to Buckland's Beach (a popular picnic spot
out of 1900's Auckland - now just another suburb of the sprawling
city).

She was floated off at high tide.

It's a reasonably clear shot of the underside of the hull but rudder
detail is still difficult to make out - I've left a supersized shot
in the folder for immediate viewing and will remove that in a few
days.

There are two islands in the background - Brown's, and what looks
like the south end of Motuihe - and the position of these suggest
that the ferry was travelling away from the position of the
photographer when she struck Flat Rock.

So I'm not sure if the dark part of the hull at the 'stern' is damage
or some quirky hull construction to accomodate the rudder. Any
thoughts?

many tks
Tony
Auckland, NZ

[Paulrjordan]

Hi Tony:

I've spent an hour staring at that supersize pic of the
stranded "Britannia" and that whole area round her rudder is baffling.

Let's first look at the possibility of damage to that area(and it
certainly looks like it). You say she was floated off "at high
tide." Is there any record of how long she stayed stranded? Was she
floated off at the next high tide. This timing is critical to
assessing if there was time to repair this so called "damage" which,
if it is so, is extensive. If the ship was refloated on the next
tide (within hours of her stranding) it's unlikely that "damage" of
this severity could have been fixed in time. If there is a gaping
hole in her hull as it looks like then you'd have expected to see
some kind of work being done to her to prevent an ingress of water at
the next tide.

Next thing...what was the nature of the grounding? This appears to be
a completely flat rock with not projections or snags to be seen
anywhere in the area. The nature of the grounding and the terrain on
which she sits does not seem to be consistent with the apparent
damage, especially as you suggest this might have been her stern
because she was heading away from the photographer's position.
That "damage" appears to be severe impact damage and more consistent
with that suffered to a bow rather than a stern.

Finally if she suffered a hole that large while afloat, the amount of
water she would have taken in would likely have placed her in great
peril of sinking before the tide left her stranded. Is there any
mention of the records of her being holed?

Frankly I don't think it's a holer. So if we consider it's NOT
damage, then what the heck is it? Can it really be some kind of
strange hull configuration around her rudder area? If so, for what
purpose? Is there any other evidence to support this? Incidentally,
on taking a closer look, it appears as if there's a figure leaning
against the rudder.

I know your dilemma here, Tony, you're hesitant to model her
underwater profile if there is any possibility that this dark area is
in factr some kind of wierd hull configuration.

The only real answer to all this would be her plans and these must
exist somewhere. Sorry I couldn't be more helpful, but this is a real
poser.

Regards

PJ
Victoria, BC Canada

[Sandy Johnston]

Further...

Using Photshop and the levels and contrast tools I believe there
are 2 figures in the dammaged area. with their backs toward us.
(Blown up to 200%)
figure 1 on the left - reaching up with bent right arm and left arm
slightly outstreached
figure 2 bending over infront of figure 1. you can see the bent
knees and the hip area only. It looks like it is working infront of
figure 1

regards
Ekelfekin
AK NZ

[wsnowdon]

Hi folks, could I add my little piece? I think this is the bow, and
what we are looking at is the shadow of the rudder aperture, with the
rudder turned away from us. Bow rudders tended to be set into the
hull with a protecting bar wrapped from the stempost to the keel as
bow rudders were Very vulnerable and would not project outside the
line of the bow. If you look, there is a vertical which doesnt appeer
to have any damage to it. I dont think a hole that size could be made
without major distortion of the "stem" bar. Also if you look at the
awning bars, they are behind the funnel. I think we are looking at
the bow with an aperture and a dark shadow. Regards, Walter

[Derek Warner]

Hi all - did double enders have leading or trailing rudders? ie., [ a conventional single vessel (paddler or not) has the rudder post fwd of the rudder
therefore it is trailing] - I cannot see enough of Britannia's bow to determine what she had

No whilst I understand if double enders by design had both trailing rudders, when in motion the aft rudder becomes a leading rudder

I ask this as the loading on trailing rudder is simply the mechanical advantage applied to the rudder blade surface and the net effect of attempting
to changing the direction of the mass of the moving vessel where as a leading rudder has the mass of the moving vessel literally trying to increase
the rudder angle further [or break the rudder blade from it's post] - Derek

[Tony Mattson]

Hi Paul, Walter, Derek and all PDers,

well I have opened an interesting can of worms haven't I?! I might
start at the end and work backwards if I can...

Firstly, leading versus trailing rudders.

I have a few photos and drawings of double ended ferries operating in
Auckland. These include side wheel paddlers and screw driven
passenger and vehicle ferries. All three types seem to have the same
rudder arrangement.

The rudder post and pintles are inboard, towards the centre of the
boat, just like a "conventional" vessel. This is what Derek refers to
as trailing rudders. The same set up occurs at both ends, just like
the British Paddle Tug AID - hence my interest in AID's lines.

Each rudder was manually engaged or disengaged by a deckhand through
a small access hatch on the deck above the rudder post. Whenever the
ferry was in motion the leading rudder was disengaged and locked in
place so that it became an extension of the keel. Only the trailing
rudder worked. This avoided the problem that Derek raises.

I assume that AID would have been set up similarly.

From a modellers perspective, disengaging a rudder each time you
change direction would be a challenge, although not insurmountable.

One of my clubmates has taken the simple route - he has a double
ended scre-driven model car ferry with both rudders operating
together i.e. two rudders, two servos and a Y lead from the Rx. The
rudder pintles and gudgeons are overscale for strength but that's the
only modification. Quite manoeverable as well! (He also has both
props working together - two motors, two screws and a single ESC, a
classic pushme-pullyou).



Next: bow rudders and protective bars.

I'm inclined to agree with you Walter. The seven stanchions nearest
us were at the bow end in the shot of Britannia taken in the 1890's
as she headed towards Devonport.

But the comment stand - which end is the bow on a double ender? The
designation bow and stern gets a little arbitrary at this stage. I
suspect that below the water, there was no perceivable difference in
design - just as Paul has said re AID - literally two sterns joined
together.

Interestingly, none of my pictures of these ferries show protective
bars. As you say this leaves the rudders very vulnerable to damage.



Finally Paul, an hour spent looking at THAT photo! That's dedication
and I salute you!

The geomorphology of the area where she grounded is accreted sand and
mudstone worn smooth by time and tide, and relatively flat - as the
name Flat Rock would suggest. There are lava flows further up the
harbour but none extended into the area where Britannia went aground.

Time up on the hard? I don't know but I suspect that it was the next
high tide as there was no mention in the reports of holing. However
these reports were not transcriptions but reproduced captions. I may
need to get into our public library archives to find original news
reports.

I agree with you and Walter - I don't think this is a 'holer' the
shape of the shadow just below the waterline seems too regular to be
anything other than design - but what a design element!

The only thing I can think of is that the hull nipped in at each end
below the waterline, to provide space for a rudder post. The nearest
equivalent might possibly be something like the USS Monitor, which
was more like a raft on top, extending outboard of the hull all round.

The later screw ferries were much simpler as they had counter bows at
each end with a vertical keel or fin extending down. The rudders and
screws were located in those fins. Britannia had a vertical stem and
if she was anything like her contemporaries and PT AID she had
trailing rudders.

Paul, I'd love to find those plans as they'd answer so many questions
for us all. Unfortunately a hundred and twenty years have passed and
our immigrant ancestors had much less respect for the heritage of
these things. So no luck in the last couple of years of hunting.

Please have a look at the PS Eagle photo folder for the design of the
double ender ferries EAGLE and OSPREY - these came from Auckland
Museum (originally penned by James Trevithick, grandson of Robert
Trevithick, the engineer and inventor - James was one of our early
immigrants). The rudder location and configuration is there but no
section lines, gosh darn!!

At least the gross shape of the hull is clearer now.

Gentlemen, I'm overwhelmed at your interest and support. Thank you
all. Clearly progress reports will be in order.

Just in passing, hull work, sponsons, paddle boxes and sponson houses
on PT Reliant are now complete to paint stage and the superstructure
is taking shape nicely. Will post updates shortly.

kind regards
Tony
Auckland, NZ

[Derek Warner]

On Friday, April 02, 2004 9:05 AM, Tony Mattson wrote :
--------------------------------------------------------------------------------

A) Each rudder was manually engaged or disengaged by a deckhand through
a small access hatch on the deck above the rudder post. Whenever the
ferry was in motion the leading rudder was disengaged and locked in
place so that it became an extension of the keel. Only the trailing
rudder worked
+
B) One of my clubmates has taken the simple route - he has a double
ended scre-driven model car ferry with both rudders operating
together i.e. two rudders, two servos and a Y lead from the Rx. The
rudder pintles and gudgeons are overscale for strength but that's the
only modification. Quite manoeverable as well!

------------------------------------------------------------------------------

Hi Tony - the point raised @ A) is a strange one - I don't know how the Board of Trade would have
allowed a rudder that was disconnectable to be used in open ocean work & would have followed
similar lines of directives that stated paddlers were not to use independent wheel operation in
open waters [this second point is well documented in ou archives]

What your clubmate has done is essentially what modern day screw double enders do, althought
naturally through hydraulic control - one simpler method for model application would be one servo,
two rudders, two motors & one speed controller - the advantage here is lower load on the single
servo due to the natural balancing effect between the resistance of the trailing rudder to move &
thus being transmitted to the leading rudder as the same resistance value but in the opposite
direction etc

I will respond to Sandy under seperate cover to ask or better understand how he got the snap
of Britannia into PHOTOSHOP & found the two workers - Derek

[wsnowdon]

I have just been through Dennys Lists and have found one NZ double
ended sidewheeler built by them for the NZ Agricultural Co. Initialy
named OCEAN she was renamed COLEEN when assembled by Sparrows of
Dunedin.( built 1879 on the Clyde and shipped out in sections) 80
foot long Rudders were recessed into the bow and stern (both
identical) with the stem bar extending over them to the keel as
protection. There is a small plan in the Dennys catalogue and the
National maritime museum have lines/GA and sections plans plus plans
of machinary. Hope this is of use, Walter.

[wsnowdon]

I have searched the plans lists and have come up with two more true
double ended paddlers. Both built as seagoing cross channel ferries.
1, PRINCESS HENRIETTA 1888 built for the Belgian government. 300 foot
long sidewheeler. When built she was the fasted merchant ship in the
world and only the latest torpedo boats could keep up with her. A
true double ender , with recessed rudders, protected by a bar stem.
The rudders were wedge shaped in the vertical and horizintal plains
(Quite thick) so that they flared into the hell shape without any
bumps or bulges!
2. DOVER and CALAIS 1895/96 200foot long. Sidewheel double ended
sidewheel ferries. Recessed rudders as for the above.
Plans for both of them are held at NMM Greenwich.
Also in the plans catalogue is a very detailed plan of the
comstruction and mechanism of a bow rudder. Lots of detail in this.
If I can get Eddy to scan it I will have it posted.
There are twenty plus other paddlers in the lists with bow rudders,
none are double enders . Incidentaly, on most British paddlers with
bow rudders they were intensely disliked as they were too vulnerable
to damage. Regards, Walter.

[Tony Mattson]

Walter, you are a gem! Wld be fascinating to see what Eddie can
produce. And then on to the NMM for me!

Thanks also Sandy for the photo forensics - unfortunately the photo
image must be 4th or 5th generation and is pretty indistinct - I'd
like to find the original news report and let you loose on that!

This thread on bow rudders has been fascinating and educational for
me. Many thanks to all. As you say Walter those bow rudders must have
been so vulnerable. I've found a few records of them jamming - and
think that must have been due to the problem that Derek identified -
with the mass and momentum of the ferry forcing a trailing bow rudder
hard over despite the disengaging mechanism.

The majority of the damage done by errant skippers seems to have come
from misjudging their speed or distance - seems that at least once a
year a double ender would reorganise the ferry landings!

grateful thanks again to all and have a great weekend

kind regards
Tony
Auckland NZ

[jamesgardiner]

Hi Tony Re: Trillium rudders. Speaking to one of the captains , at
the Toronto Marine Historical Association, he said " one of the crew
members used a long pole to reach the locking mechanism to lock the
lead rudderone the double ended ferries.This applied to both the
diesel and steam double ended ferries in service today. When the
Trillium was rebuilt electrical locks took over the manual locking
system and as somebody else suggested the lead rudder became part of
the keele. To compensate in docking bow thrusters were added during
the refit. The Bow thrusters one at each end , were water is drawn in
and out on the same side operated by diesel engine.The bow thrusters
are placed one one each end[ oppsite to each other. Take care Jim
Gardiner