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Need help with finding a suitable replacement, or how to lay up a new rudder, specs etc. any and all help would be great. Husband is with Eole in the USVI, Eole is a 1973 ketch, dickerson of course, otherwise in great shape after 10 yrs of refitting. Made the 1500 from Hampton Road to BVI in 10 days, 6 hrs and 49 minutes. After a lovely 5 days, meet with a nasty situation and the boat will be hauled next week in St. Thomas.
Hi Caroline,
Ouch…..Sounds like the sail down was wonderful. It was 24 degrees in Concord NH today – I want to be you guys!My wife and I own a 1973 36 foot Ketch – It’s sitting in the driveway in front of the house; Here are some measurements I just took off the boat…..
I rebuilt my rudder 3 years ago because the rudder post was cracked on a grounding a few years back when we were just a bit north of Norfolk, Va. I tore the rudder apart to replace the top post & flipped the bottom post/pin to eliminate “wobble” in the shoe. The rudder is a foam composite – foam core, with a very simple attachment for the top post – Dickerson put a bend in the rudder post about 2 inches below the top of the rudder and “bent” the post at about a 60 degree angle into the body of the rudder. The “bent” section is about 15 inches long – there are no other “ribs/stringers” that you might find on a spade rudder – my feeling is that this is not a highly stressed rudder. The top post is 1.25 inch (Dickerson used Tobin bronze, I replaced with stainless – I used an old shaft that someone gave me because it was scored in places but not an issue in this application. That might be a cheap out for you in the islands….
The bottom of the rudder is held in the shoe by a 8 inch long piece of bronze rod that is glassed in place on the leading edge of the rudder – the rod extends about 1 inch out of the rudder and fits into the hole in the shoe. No bearing..
Some dimensions:
A. The rudder is a bit over 1.5 inches thick on the lead edge & tapers to about .25 inch on the trail edge.B. To get your “top length” of the Rudder – The top of the rudder extends aft 14.5 inches from the front of where the rudder post exits the boat.
C. So….. 1. Take a 1/2 inch thick board 3 feet long and sit it on the top of your rudder shoe – hold it level (block it up with a cinder block or wood scraps). Have it follow the line of your keel. (this will give you your bottom edge for your rudder).
2. Cut a 14.5 inch long board & hold 1 end to the the front of the hole where the rudder post exits the boat & hold it level, at the aft end of this stick drop a plumb bob (or level) straight down towards the ground. This gives you the rudder top dimension, trailing edge & bottom of the rudder – The bottom aft edge of the rudder is 6 inches forward of this (plum bob) line. The aft edge of the rudder does not drop straight down, it angles forward a bit. So, measure back towards the keel on the bottom board, 6 inches from the “plum bob” line – this is your rudder dimension. The bottom of the rudder is pretty much level and follows the keel, but sits about 1/2 inch above the shoe.D. For the Prop opening – Measure from the top of the shoe up 20 inches – that’s where the aperature opening for the prop starts. The aperature opening extends aft 10.65 inches and drops a bit in this 10.65 inches – it drops 2 inches from bow to stern – measure up from the bottom of the rudder 18 inches for the stern end of the bottom of the aperature – that’s your mark. Our rudder has a radius of about 1/2 inch where the horizontal rises into the vertical on the aft corner of the prop aperature.
The top of the prop opening (aperature) starts 7.25 inches below the bottom of the boat and is pretty much an arc that blends into the trailing edge of the aperature.
E. The Leading edge of the rudder face in the aperature is 3 3/4 inches aft of the back face of the Prop (the prop nut fastens up to this face). The thickness of the rudder here is also about 1.5 inches. The “Leading edge” of the rudder in this aperature is pretty much parallel to the Prop blades. This angle is a bit different than the angle of the leading edge of the rudder….
Our rudder is a foam blank that had a couple of layers of 6-8 oz cloth over the whole thing – with a bit of fiberglas (looked like a bunch of mashed potatoes plastered in place) reinforcement where the rudder post was bedded in the foam – a lot less than I expected.
When I replaced the top rudder post i did it pretty much “on the boat” since I could not “drop” the rudder – I cut the old post out in place, replaced the post on the boat & rebuilt the rudder in place on the boat – Eliminated any “alignment” issues, since I could see everything as I went along & adjust as needed…..I bedded our new post into the foam rudder in a mix of epoxy & cabosil – clamped it in place over the rudder post to make sure all was fair. let it all harden. Then re-wrapped the rudder in a couple layers of glass & west epoxy & added a couple/3 additional layers on the top 1/3 of the rudder where the post was – then faired it all smooth & painted it with some epoxy paint I had lying around…. Looks nice, & has worked fine for 3 years.
I suspect you could make a new “foam” rudder out of construction foam panels. 2 3/4 inch panels sandwiched with some reinforcement where the post sits – bend the top post – that gives you the angle, rough out the panels & press them against the post – then rout out where the post sits….reinforce a bit with epoxy/glass – screw the 2 faces together with epoxy on the faces….Fair to size with an autobody grinder & 7 inch disc….Coat in glass & epoxy.
Or, build it out of plywood in layers, rout out where the top/bottom posts go – fill the routing with epoxy & cabosil to fill & hold everything in place – then cover the whole thing in epoxy & glass….
Just some thoughts……Oh….The thickness of the rudder tapers only in the last 6 inches of the rudder. It holds the 1.5 inch thickness throughout the body of the rudder & in the last 6 inches it tapers to about .25 inch.
We repaired our rudder in a boatyard in Norfolk Va after a grounding 6 years ago. Tore the top of the rudder apart, Bent the rudder post & cracked the rudder near the pin that fit into the shoe – I used a Wood chisel to cut the post out – a torch to bend the post straight (big hammers & backing plate) & epoxy & glass to hold everything together for the trip to Massachusetts. A couple years later I tore the whole rudder apart to “fix” the repair – these are pretty simple, low stress rudders.
If I were doing my rudder again I’d think hard about extending the rudder about 3 inches and put a radius on the bottom edge that rose 6-7 inches towards the stern – so if I grounded the rudder would be up off the bottom a bit more out of danger – Cape Dory & Allied do that on some of their bigger boats…. easy to calculate the area. Although the additional surface area would be a bit farther aft ……..I’d probably replace 80% of what I removed from the bottom.
Hope this is helpful….If you would like any additional measurements, ect give me a call on My Cell # 603-225-7999 & I will help as best I can. If you want I can e-mail a picture of this to you so you get a better feel for these dimensions…….E-mail BoatsNH@yahoo.com
Mike
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