New grp spade rudder

[rogerthebodger]

One of the points I was making is that a hollow rudder will float so no extra weight aft.

I do take the point about the aluminium rudder tube and stainless rudder shaft.

Don't know the exact shape of the existing rudder but an approximation to double curvature can be achieved with cut and weld fabrication if it is really needed which I would question.

Just really questioned why GRP boat rudders should be made a different when they seem to fail due to water ingress into the foam structure.

 

[TSB240]

I fully understand the implications of weight in the ends of any boat, racing or cruising, but I remember when carbon fibre rudders began failing on racing boats; from my aviation experience with this nasty material, then in its' infancy for maritime use, I thought ' could have told you that ' with a cringe.

OK I'm a cruiser at heart, but a fast cruiser who has sailed plenty of performance boats; one thing I would never skimp on, as it's rather useful all the time and can endure even higher loads on racing boats, is the effin' rudder !

So much for German uber-engineering if they use alloy stocks, sheesh !

In the OP's situation, both for getting out of the present predicament & future use, I'd quite fancy the all stainless rudder inc blade idea.

If this sounds like too much weight aft, many people are happy to carry a liferaft on the transom...

Has the stock broken?
I wouldn't prejudice the situation until the Op updates us on the actual damage.

 

[Daydream believer]

So how many of the mass produced AWB's use stainless steel stocks?
I do however, admit that i have always considered my rudder a liability. The bottom of it is 50 mm above the bottom of the keel. I think if i had to use a drogue in big seas ( my boat will not heave too ) & the boat was knocked back a bit as it would with a drogue then the weight on the rudder would be like reversing too fast & smash it to bits
That is one real problem with spades ( rudders)
In having a new one i am going to specify it 4 inches shorter
The stock is perfectly ok but the needle rollers in the top bearing have been dislocated on one half so i need a new top bearing

 

[Herald]

Yes autopilot suddenly went haywire veering 20 degrees off course each way ( i reported this on another thread) as i went to disconnect i went aground, ,,quite gently ,, i was not worried at first as i went to motor off. However tide was so strong that it forced me right on to a bank & heeled over 15 degrees. The rudder & keel hit some rocks. Not that hard so even then i was quite relaxed just bemoaning my carelessness. I prodded with the boat hook & it seemed to be sand & shingle. The tide actually dragged me quite a way onto the bank from where i touched. It did jerk the rudder a few times as well as the keel
I floated off 3 hours later i actually hoisted mainsail & sailed off not even bothering to motor. I had reported situation to CG. Do not know why really i suppose i wanted something to do whilst i was sitting with a cup of coffee in my hand.
When i came off i reported i was on my way & no problem. 15 mins later a thump as if i had hit a pot . Looked aft. & saw my rudder floating away. I was able to call cg & did not have to waste time with details as i had already given them. RNLI turned up inside 15 mins& as usual they were brilliant dealing with everything for me
Odd thing was that the chap that came aboard used to live 5 miles from me in essex
As it is sunday i have not been able to speak to Hanse team but have reported to insurers GJW on their hotline. That worked ok so i am hoping it will get sorted efficiently

Just of interest, whereabouts were you when you went aground? Not too many rocks to hit in Moray Firth generally sand and some shingle.

 

[Daydream believer]

Just of interest, whereabouts were you when you went aground? Not too many rocks to hit in Moray Firth generally sand and some shingle.

Just east of kessock bridge so really it is inverness Forth. The whole of the centrel is shallow - about which i was perfectly aware having been there before. It seems that there are isolated rocks on the sand. When i prodded with my boat hook it certainly felt like shingle. The boat kept banging them as the tide pushed me up the shallow slope. But the banging did not seem really bad. It was just a tide rip pushing & turning the boat that caused it. Once on the sand it is a long way off & one would not know the direction. Trying to turn the boat towards the channel was impossible so i did not try too hard. I just accepted i had cocked up & made a coffe

 

[Herald]

Just east of kessock bridge so really it is inverness Forth. The whole of the centrel is shallow - about which i was perfectly aware having been there before. It seems that there are isolated rocks on the sand. When i prodded with my boat hook it certainly felt like shingle. The boat kept banging them as the tide pushed me up the shallow slope. But the banging did not seem really bad. It was just a tide rip pushing & turning the boat that caused it. Once on the sand it is a long way off & one would not know the direction. Trying to turn the boat towards the channel was impossible so i did not try too hard. I just accepted i had cocked up & made a coffe

Thanks. Presume you were between Kessock Bridge and Meikle Mee SHM. Bottom is definitely shingle in the Firth have hit the bottom on the skate bank when racing before...... The tides can be fierce as well. Hope you get it sorted soon enough. I'm sure David and the team at the marina will be accommodating enough.

 

[Daydream believer]

I hope you get this sorted and I have a keen interest in your solution. I had only last weekend visited the Jefa site for considering a future replacement .
http://www.jefa.com/rudder.htm.
They seem to offer an off the shelf solution to more than 1 or two mainline boat brands.

When you say you saw half the rudder float away. Was this broken off horizontally or was it delamination off the aluminium stock/frame

The split was vertically on the joint between the 2 halves
I just wish i knew how to post a photo off an Ipad

However, update is that i have 2 options
I have a cheep quote ( return load) of well under £2k to take boat back to Bradwell where i can have the work done at leisure & avoid storage costs & logistical costs . Take into account day sailing home over 3 weeks with all ancilliary costs etc will be nearly a grand this is an option. The insurers have agreed to accept tjis
The other option is to let Cally Marine do the whole thing which they say they can do in under 3 weeks. They even have managed to source a neoprene skirt for the rudder tube & will do the bearings etc.
They also offer a deal on 1 month storage.
Having spoken to their manager i have some confidence & his approach to this was professional as was his inspection of the work. How he managed to get in & out of the stern locker was a mystery!!
I am awaiting a quote tomorrow. It eill not be cheap but they offer a full package
If i went home i would get the rudder done by G Eeles of Brightlingsea. I had forgotten him & a suggestion that he might do it has been confirmed. He did work on my Phantom dinghy he did it exactly on the days he said he would & his work put a grand on the value of the boat. However he would not do the fit etc & i would have to do that as well as source the skirt & bearings etc & get the boat lifted to put the rudder back on

 

[Daydream believer]

Thanks. Presume you were between Kessock Bridge and Meikle Mee SHM. Bottom is definitely shingle in the Firth have hit the bottom on the skate bank when racing before...... The tides can be fierce as well. Hope you get it sorted soon enough. I'm sure David and the team at the marina will be accommodating enough.

Checking the chart it was on the Meckle Mee just NW of the stbd hand buoy for which i was heading.
The tide was v strong & because of the agro with the d..d autopilot i was not watching how much i had gone off course
I think the rocks are probably large boulders, for want of a better term, bought down river by the tides & bedded in the shingle. Yes the "team" do seem professional & unlike many marinas have in house capabilities about which i was not aware. It is now all down to cost & time

 

[Seajet]

So,

Who was the manufacturer

How old was the boat

How much support did the owner get

What was the build quality of the initial rudder assembly

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

 

[Daydream believer]

So,

Who was the manufacturer

How old was the boat

How much support did the owner get

What was the build quality of the initial rudder assembly


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

Hanse
11 years (one owner)
Did not ask manufacturer for support. The Hanse owners forum is very good. & information suggests manufacturer support would be lacking
Looking at what is left - not particularly good. Especially considering the fairly light grounding

 

[TSB240]

If its any consolation GJW paid up with no quibbles when I had a big claim last year.They were very efficient on all counts.

 

[Seajet]

Hanse
11 years (one owner)
Did not ask manufacturer for support. The Hanse owners forum is very good. & information suggests manufacturer support would be lacking
Looking at what is left - not particularly good. Especially considering the fairly light grounding

I doubt any decent engineer would have problems forming a stainless ' teardrop ' aerofoil shape over a moderate internal structure of lateral webs, might take a bit of sketching & planning & that's it; however I understand you're getting the boat transported to somewhere local which can't be a bad thing apart from a dent in voyage plans...

I must say this is not a good advert for Hanse, they really shouldn't use alloy in any part of the rudder assembly.

 

[TSB240]

An excerpt from Jefa....

"Historically stainless steel 316 has been the preferred rudder shaft material. This material was chosen as it was non corrosive and relatively strong and widely available. At the end of last century alternative rudder stock materials like aluminium and high strength stainless steel became widely available.
Driven by the aircraft and space industry, new high quality aluminium alloys were developed. Some of these alloys turned out to be perfectly suitable for rudder shafts and other parts of sailing yachts. Gradually all big boat yards making GRP yachts converted to aluminium rudder shafts. But still some people, especially some designers, doubt about the use of aluminium as rudder stock material.
The purpose of this page is to present a clear overview off all material characteristics so one is able to make a clear choice based on facts and not on rumors."

http://www.jefa.com/products/materials.htm

Conclusions:

Aluminium 6082 rudder shafts are strong, light and economic and ideal for cruising production yachts..
If stainless steel is preferred, one should use stainless steel AISI 329.
Stainless steel 316 rudder shafts are NOT stronger than aluminium 6082 rudder stocks.
Very thin rudder blades can only use the ultra strong stainless AISI 630 which has some small corrosion issues. (See the above text how to avoid this).
All measurements to avoid corrosion can be found on our electrolysis page.

 

[Daydream believer]

I doubt any decent engineer would have problems forming a stainless ' teardrop ' aerofoil shape over a moderate internal structure of lateral webs, might take a bit of sketching & planning & that's it; however I understand you're getting the boat transported to somewhere local which can't be a bad thing apart from a dent in voyage plans...

I must say this is not a good advert for Hanse, they really shouldn't use alloy in any part of the rudder assembly.

How would electrolysis work with stainless steel 3 ft from a bronze prop, an aluminium saildrive & coppercoat antifouling & dzr seacocks

What with salt water & a bit of shore power i should be able to run a boat load of LED's off that lot

 

[rogerthebodger]

I would question some of the statement made on Jefa web page and would like VyV_cox to comment as well.

" Another important comparing factor, besides the mechanical properties, is the price of a rudder stock. In order to make a complete comparison between the four "

The second part of this statement IMHO is more to the point.

" The protection against corrosion is not achieved by an oxide layer like aluminium, but the added chrome and nickel make sure the metal itself will not oxidise. We use the following types of stainless steel: "

I was under the impression that it is the layer of Chrome oxide that instantly forms on stainless steel in an oxygen environment that is the prime protection for stainless steel.

A Foam/GRP cover of the typical AWB rudder once cracked allowing water to enter is an ideal environment for crevices corrosion to occur as it creates an oxygen depleted environment.

VyV_cox web site does describe this in detail

Also when welding stainless a low carbon gives better results as I understand the corrosion at the welded joint is less with the low carbon (316L) rather than normal 316

 

[rogerthebodger]

How would electrolysis work with stainless steel 3 ft from a bronze prop, an aluminium saildrive & coppercoat antifouling & dzr seacocks

What with salt water & a bit of shore power i should be able to run a boat load of LED's off that lot

IMHO a good boat design should limit the number of different metals below the waterline.

On my steel hull boat I have all 316 stainless including my prop. The only yellow metal is my Vetus bow thruster leg which is bronze of some kind

 

[Tranona]

I must say this is not a good advert for Hanse, they really shouldn't use alloy in any part of the rudder assembly.

Aluminium is used extensively for rudder stocks - and has been for many years by builders in all price/quality ranges.

 

[Tranona]

How would electrolysis work with stainless steel 3 ft from a bronze prop, an aluminium saildrive & coppercoat antifouling & dzr seacocks

What with salt water & a bit of shore power i should be able to run a boat load of LED's off that lot

Don't think it is electrolysis that is the worry, but crevice corrosion on stainless, which can happen if water gets into rudder moulding or around bearing areas where you can get stagnant water.

 

[Seajet]

Aluminium is used extensively for rudder stocks - and has been for many years by builders in all price/quality ranges.

I am experienced and trained / qualified re alloy & stainless; you feel free to walk out on an alloy plank which has lived in salt water, extended from a skyscraper roof; I'll have the stainless one thanks...

 

[TSB240]

I dont think the Op is particularly bothered about replacing something that has worked for the last 11 years with the same design without fault or failure.

He has reported the main problem as the separation of one half of the blade from the supporting frame and mating side pair. This probably has absolutely nothing to do with corrosion of Aluminium. The damage was caused by mechanical impact with either rocks or a shingle bank FCS.

Following the logic of recommending any brand not using aluminium would probably exclude a purchase decision involving
Bennies, Bavies, Jennies, Dehlers, X Boats, Najads, Farrs, Wauqiez, Standfast, Etap, and Hallberg Rassey....

So that just about leaves you Errmmmmmm.....

Oh an Anderson 22.:encouragement:

Making plastic and Metal assemblies work reliably remains an issue for even the biggest players

http://aviationweek.com/awin/a380-wing-repair-costs-escalate-emirates