It seems like HDPE may just not be a suitable material for rudders in the thickness commonly used for this size of boat. It looks like it fatigues right where support from the stainless cheeks stops; right where you would expect. It seems to hold up well on smaller craft where the rudder is proportionally much larger. Its too bad since it made such a nice blade. Hopefully someone will come up with a clever design idea or maybe a replacement plastic. A nice thing about these events is that they test the boats beyond the limits that most of us use them and we learn a lot.
One thing to consider is the R2AK M 17 (built 2008) used an older 'standard' Idasailor rudder. We've installed lots of these standard Idasailor rudders without issues. In fact we have 2 on order with Ruddercraft right now. What the boys should have used is the Ruddercraft BLUEWATER model, which has more strength, thicker sections, thicker stainless and suitable for extreme bad weather. In any case they did a fantastic job on their Adventure... Bob Eeg Sent from my iPad
On Jun 29, 2015, at 12:45 PM, jnschum <jnschum@olympus.net> wrote:
It seems like HDPE may just not be a suitable material for rudders in the thickness commonly used for this size of boat. It looks like it fatigues right where support from the stainless cheeks stops; right where you would expect. It seems to hold up well on smaller craft where the rudder is proportionally much larger. Its too bad since it made such a nice blade. Hopefully someone will come up with a clever design idea or maybe a replacement plastic. A nice thing about these events is that they test the boats beyond the limits that most of us use them and we learn a lot.
I don't know if anyone is using it, but fiberglass reinforced nylon injection molding is probably going to be a lot lot stronger for relatively long thin foil shaped sections. I'm not sure of the details but I think that is one flavor of RIM (resin injection molding) technology. It is used for high strength high quality lower price point (than pure glass or carbon fiber) paddle blades (kayak/canoe). I've never seen anyone use HDPE for that and I can't imagine it would work well. cheers, John S. On 06/29/2015 12:45 PM, jnschum wrote:
It seems like HDPE may just not be a suitable material for rudders in the thickness commonly used for this size of boat. It looks like it fatigues right where support from the stainless cheeks stops; right where you would expect. It seems to hold up well on smaller craft where the rudder is proportionally much larger. Its too bad since it made such a nice blade. Hopefully someone will come up with a clever design idea or maybe a replacement plastic. A nice thing about these events is that they test the boats beyond the limits that most of us use them and we learn a lot.
-- John Schinnerer - M.A., Whole Systems Design -------------------------------------------- - Eco-Living - Whole Systems Design Services People - Place - Learning - Integration john@eco-living.net - 510.982.1334 http://eco-living.net http://sociocracyconsulting.com
Using West System G/Flex epoxy, it would be possible to shealth an HDPE rudder in fiberglass, if the HDPE were first flame treated. I have glued blocks of flame treated HDPE directly to fiberglass with G/Flex, and the joint seemed as strong as the materials themselves. Tyler
On Jun 29, 2015, at 6:11 PM, John Schinnerer <john@eco-living.net> wrote:
I don't know if anyone is using it, but fiberglass reinforced nylon injection molding is probably going to be a lot lot stronger for relatively long thin foil shaped sections. I'm not sure of the details but I think that is one flavor of RIM (resin injection molding) technology. It is used for high strength high quality lower price point (than pure glass or carbon fiber) paddle blades (kayak/canoe). I've never seen anyone use HDPE for that and I can't imagine it would work well.
cheers, John S.
participants (4)
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Bob Eeg -
jnschum -
John Schinnerer -
Tyler Backman