Roberts Mauritius / Norfolk Rudder Modification

"Kupere"
Airlie Beach
12/04/99

Dear Phil

Firstly many, many thanks for your help, etc over an alternative rudder. The deed can be done and "Kupere" is like a new boat!

We can leave the helm and on she goes, the wind vane works like a piece of cake and the weather helm reduced by about 80%. A broad reach in 20 knots has gone from about 15-20 degrees of rudder to 5 degrees!! The total cost $1445.00 for a welder and steel.… took 5 & ½ days to complete.

Really thrilled with results Phil and really appreciate your time in faxing the data. The details of what I did are below, so if you have any further enquiry’s you can advise them accordingly.

I measured the rudder up before the change, and it appears that it was too short in height by about 200mm which might account for some of the problem I had. I put 100mm of leading edge onto the new rudder- a conservative move in line with the 1/5 to 1/7 rule. I used 1/7th.

I’ve reused the old bearings post and just enlarged the old rudder. Had a bit of fun re aligning the sleeves for the steering cables, but it would appear I got it pretty right – no wear at present.

I’ve taken a bunch of photos before and after which I’ll forward.

From here we’ll probably head down to Bundy, then head to Vanuatu. Will make sure we meet you on our path.

Cheers

Martin

      Hauled and water blasted                                                               The Mauritius's underwater lines

 Showing clearly the additions                                                   Note the now vertical rudder post

All primed and ready.                                                                                  Finished job.

 Here are the photos. You can clearly see the
webbing we put on to increase the stiffness of the heal and how we spigoted
the heal extension back into the existing keel.  We also managed to plug
weld it to the t section in the keel shoe.

And from Jim in Florida who also undertook to modify his rudder position.

Thanks a lot.  I will be glad to extol the virtues of the modification to him.  The boat is so much easier to handle now.  Before the modifications I couldn't stay at the helm for more than 3 hours without being tired to the bone from the "wandering"  But on my last outing I was at the helm for 12 hours, tired, but no sore shoulders from fighting the helm. 

And also from Paddy who undertook to do the modification in New Zealand.

With the rudder mods. We spent 10 days sailing over Xmas in a variety of conditions.  I would consider the results highly successful.  Boat speed is a lot better, up from a max of 7 knots to a max of 8.5, with a similar increase in cruising speed from 6 knots to 7.5.  The weather helm is much reduced, although still noticeable, particularly if pushed hard and the boat is quite heavy on the helm, understandable considering the size of rudder she now has.  She is also still a bit tender, particularly in a following sea but this is manageable as opposed to being just impossible before.

We get a pretty good variety of sailing conditions here, including some quite challenging weather and swell conditions.  I feel the boat is more than up to these and am very happy with the mods.  I have finished the film which I used to take a couple of photos of the work and will send you a couple of shots once they are developed.

Interestingly the concerns I had about manoeuvrability under motor were not realised.  She is a lot better in the marina and I can steer both to port and starboard when going astern, provided there is no wind.

Total cost for the job was around $5k NZ but as I mentioned we did do a lot
of stiffening and this takes a lot of time due to the extra welding involved.