Boatmik
24th March 2008, 03:10 PM
Howdy All,
Good little story here.
Got this email from Jonathan Bornman whose sons have been building two OZ PDRs in Africa.
http://farm3.static.flickr.com/2179/2356973644_1dcc471779.jpg
They went sailing for the first time and used the "wrap sail around mast" reefing method I used after my PDR speed record attempt. While I wouldn't be planning to get upwind under such a rig - returning home on a reach or a run seems to work quite OK.
http://farm3.static.flickr.com/2319/2356141415_b4bdde3b0d.jpg
HOWEVER - they broke their rudderboxes.
http://farm3.static.flickr.com/2341/2356154039_8ee692b944.jpg
This is Jonathan's email
Hello Michael,
Here are few shots of our first attempts at sailing our just completed PDRacers. There was a stiff wind. We had fun but we also ran into problems with the rudders. The this 4mm plywood sides failed almost immediately on the first two we put in the water. The third boat never went got tested. I am sending you a picture. I would welcome your thoughts.
Thanks for a great set of plans! They were easy to follow.This is my reply (actually I sent two emails when I realised the tiller wasn't glued to the top of the rudderbox - it carries most of the loads for turning the rudder - so needs to be part of the unit.
Hi Jonathan,
Very exciting to hear the boats are in the water.
With the rudders - all the bolts need to be in place as in the drawings. The boxes are weak without them and almost indestructible with them.
None of this is really my doing - the design process was carried out over thousands of OZ and NZ racing boats where this method is still quite dominant. I saw it first on Paper Tiger catamarans in 1973 - and realised its importance as a 12 year old. I've used it on a succession of boats and slowly realised exactly what you have to do to make it light, simple but incredibly reliable.
With our original boats we did not use manufactured rudder fittings either but put lots of fibreglass tape around the front edges of our wooden rudder fittings that went back onto the rudder box.
The glass tape is entirely unnecessary if you use the fittings in the plan drawings.- shown below. This drawing is actually a little inaccurate as there needs to be a bolt through the tiller - not shown in this drawing, though one in the plan body does show it.
http://farm4.static.flickr.com/3182/2356252801_cfa780343c.jpg
You can see the pictures here of the glass taping - it was quite heavy with about 5 or 6 layers of tape built up wet on wet.
http://farm3.static.flickr.com/2368/2357042628_39d78ef49e.jpg
However some bolts and washers in the same places as the specified rudder fittings will do a good job too.
Here I think is the problem ... there is lots of glass tape in the finished pic below - but you cannot see it at all.
http://farm1.static.flickr.com/144/383639624_ca17475a65.jpg
The rudder boxes are a really good design are super reliable and completely trouble free - they work brilliantly in every conceivable condition. Please be prepared to perservere with getting them right as they are the best solution for almost every boat.
Best wishes
Michael
Sooo - thanks hugely Jonathan for the pictures of the two (!!!!!) boats - and look forward to more when you get out sailing again.
Also thanks for the photo of the failure which makes this larger article a bit possible.
Thanks again
Michael
Good little story here.
Got this email from Jonathan Bornman whose sons have been building two OZ PDRs in Africa.
http://farm3.static.flickr.com/2179/2356973644_1dcc471779.jpg
They went sailing for the first time and used the "wrap sail around mast" reefing method I used after my PDR speed record attempt. While I wouldn't be planning to get upwind under such a rig - returning home on a reach or a run seems to work quite OK.
http://farm3.static.flickr.com/2319/2356141415_b4bdde3b0d.jpg
HOWEVER - they broke their rudderboxes.
http://farm3.static.flickr.com/2341/2356154039_8ee692b944.jpg
This is Jonathan's email
Hello Michael,
Here are few shots of our first attempts at sailing our just completed PDRacers. There was a stiff wind. We had fun but we also ran into problems with the rudders. The this 4mm plywood sides failed almost immediately on the first two we put in the water. The third boat never went got tested. I am sending you a picture. I would welcome your thoughts.
Thanks for a great set of plans! They were easy to follow.This is my reply (actually I sent two emails when I realised the tiller wasn't glued to the top of the rudderbox - it carries most of the loads for turning the rudder - so needs to be part of the unit.
Hi Jonathan,
Very exciting to hear the boats are in the water.
With the rudders - all the bolts need to be in place as in the drawings. The boxes are weak without them and almost indestructible with them.
None of this is really my doing - the design process was carried out over thousands of OZ and NZ racing boats where this method is still quite dominant. I saw it first on Paper Tiger catamarans in 1973 - and realised its importance as a 12 year old. I've used it on a succession of boats and slowly realised exactly what you have to do to make it light, simple but incredibly reliable.
With our original boats we did not use manufactured rudder fittings either but put lots of fibreglass tape around the front edges of our wooden rudder fittings that went back onto the rudder box.
The glass tape is entirely unnecessary if you use the fittings in the plan drawings.- shown below. This drawing is actually a little inaccurate as there needs to be a bolt through the tiller - not shown in this drawing, though one in the plan body does show it.
http://farm4.static.flickr.com/3182/2356252801_cfa780343c.jpg
You can see the pictures here of the glass taping - it was quite heavy with about 5 or 6 layers of tape built up wet on wet.
http://farm3.static.flickr.com/2368/2357042628_39d78ef49e.jpg
However some bolts and washers in the same places as the specified rudder fittings will do a good job too.
Here I think is the problem ... there is lots of glass tape in the finished pic below - but you cannot see it at all.
http://farm1.static.flickr.com/144/383639624_ca17475a65.jpg
The rudder boxes are a really good design are super reliable and completely trouble free - they work brilliantly in every conceivable condition. Please be prepared to perservere with getting them right as they are the best solution for almost every boat.
Best wishes
Michael
Sooo - thanks hugely Jonathan for the pictures of the two (!!!!!) boats - and look forward to more when you get out sailing again.
Also thanks for the photo of the failure which makes this larger article a bit possible.
Thanks again
Michael