Chainplates

[furdui]

Hi,yamahanians,I am new at this forum,but I own a Yamaha 25 MkII for about 10 years (and for that reason I am the happiest person in the world,well,sort of).
Two years ago,in a 30+kn wind,my head stay broke away together with deck fitting,which is welded to a 30x4 mm'through deck'plate,which is bolted to the hull,under the bow. This plate was completly corroded in the area inside deck's fibreglass,with no prior telling sign.
Now,I am thinking,the chainplates can be in the same situation,although there is no sign of any corrosion,inside or outside.
My question,has anyone inspected these chainplates by dismantling them,and how is it done!!!

 

[Syntonos]

Welcome aboard ! your in the right place for Yamaha Talk. I've been on this forum for quite a while and this is the first I've heard of such a problem on any Yamaha. A couple of threads back a similar concern with chain plate wood rot was discussed.
I'm sure you have all the Y25 guys attention. Exploritory surgery is the only thought that comes to mind-- take lot's of photos and keep us informed.

 

[furdui]

Thanks Syntonos,
I am interested to know if the 4 screws holding down the 50x50 mm plate through which the chain plate comes out above deck are wood screws or they are bolts with some nuts embeded in deck's fibreglass,because I can't see any opposite nuts under deck.I need that because I suspect the plate holds the sealant around chain plate,and my boat is still very dry inside and I don't want to do anything to jeopardise that.

 

[Syntonos]

Furdui, Your guess would be as good as mine. I would figure that they use screws as the deck seems to be 7/16-1/2 inch thick on my boat in that area as determined by fuel /waste thru hull fittings. I too would be hesitant to disturb the chainplate for the reasons you describe. Pulling one fastener should'nt disturb much to resolve the question.

 

[furdui]

Hi Syntonos,looks like you've installed a navik windvane,did you install it off centre line or you've moved the ledder ,are you happy with it,do you cruise a lot,is it helpfull?
I'll be in LA net month and I hope to get a couple of days off,do you know a place where I can buy something like that or similar,preferably preloved one(aka,cheap!)?

 

[zeehag]

should be thru bolts with nuts and washers and backing plate.

 

[Syntonos]

Ok. sitting in my boat looking at all the stuff covered in the last few threads. Thanks for making me focus on the boat for a while rather than the stuff of daily "Life"

The three (3) side stays are fastened with thru bolts on the forward and aft shrouds. The center "chainplate" runs through the hull and are attached to the obvious pillars/amas (large beam supporting the mast step/hull ) The plate over the chainplate is a cover plate and held in by screws. removing one stay at a time should be no problem with halyard support (a standard practice). If you want to play it extra safe I'd run a line under the hull to the opposite shroud of the boat to spread the load rather than attaching to something like the toe rail.

Syntonos
just my 2 cents

 

[furdui]

horror

my fellow Yamaha 25 owners and others(who is not strong enough should not read or look further!)

i cut the sylicone around chaine plate,found cracks,supported beam,dismantled chain plates,all is there for you to see!
because others have not reported something similar,here is my two bob worth....

causes: --- chloride stress corrosion cracking combined with weekly club racing(more pleasure then racing!)
---oxygen starvation---embeded in glass,combined with above,or

----because it sits up side down(in comparison with most of the other Yamahas)

 

[furdui]

Furdui, Your guess would be as good as mine. I would figure that they use screws as the deck seems to be 7/16-1/2 inch thick on my boat in that area as determined by fuel /waste thru hull fittings. I too would be hesitant to disturb the chainplate for the reasons you describe. Pulling one fastener should'nt disturb much to resolve the question.

it may help,

measuring the marks on chainplate,after i pulled it down,it seems,the deck in that area is approx. 37 mm thick,and it does not look double wall,the mark is continuos.

simon

 

[Syntonos]

CHAIN PLATES ---- owners findings

Simon, Thanks for the wake up call , you've just given all us Y25 guys a weekend project! I suggest anyone checking thier chainplates drop the forum a note with thier findings. This way we can get a handle on if this is a common problem or Simon is a sailing Animal!!
By the way what shroud tensions are you running.

 

[furdui]

Simon, Thanks for the wake up call , you've just given all us Y25 guys a weekend project! I suggest anyone checking thier chainplates drop the forum a note with thier findings. This way we can get a handle on if this is a common problem or Simon is a sailing Animal!!
By the way what shroud tensions are you running.

My tension!!,I use a 'loos&co"rig tension gauge.
Pic 1, port chain plate, shows the crack on the right filled whith rust which in time oppend the crack more and more,bending the plate towards left,against the pulling of the shroud!!!!
By the way,I too like things "manual".My chain sprocket for manual start,installed on my Yanmar on main shaft together with pulleys for water pump and generator turns freely in both directions.In ten years I have never used it and unfortunately,never oiled it,lately trying to bring it to life ,with oil,too late,wd40 and even with heat and hammer knocking but no succes so far.I suspect it has a one way bearing inside and the balls got stuck in solidified oil.ANY SUGGESTIONS

Simon

 

[Syntonos]

Took a look at my manual. Sounds like you've got it right. The handshaft over the engine supported by two pillow block bearings-then to the chainsprockets that attach to the actual starting shaft which returns into the engine case. On that shaft is a roller clutch. I'll try and post pics of the manual pages tomorrow. Looks easy enough to get at, just remove the cover. unfortunatly it's on the unfriendly side of the engine compartment - toward the bow

I use a Loos guage also-- just curious what your #s are.

p.s. Love the pic of your colors on the backstay.

 

[Syntonos]

Here ya go - hand crank 101. Also included the "manual" oil filter service page located in the same area. Hope they can be read.
An old school penetrating oil trick --- ATF/ Acetone @ 50/50

Meant no disrespect with the "animal" comment. Just know you Aussies sail hard. Your Cup record speaks for itself.

 

[furdui]

Here ya go - hand crank 101. Also included the "manual" oil filter service page located in the same area. Hope they can be read.
An old school penetrating oil trick --- ATF/ Acetone @ 50/50

Meant no disrespect with the "animal" comment. Just know you Aussies sail hard. Your Cup record speaks for itself.

no worries mate !

thanks for infos,very kind of you.found out your inbord is ysm8 and mine is yse8,forgot to mention that,yesterday i found a site "engine manuals sailboatefaki.gr" very good for yse8,looks like my problem is that i have to pull out two pulleys before reaching the outer ring of the wheel sprocket.
what 'ATF' stands for?

i retract the first cause(chloride scc) in my 6-27-2011 post as 'not applicable',and if nobody comes up with a similar chainplate problem,i will retract the second cause as well in the mentioned post and i will strongly believe the third one is true!!!

for rig tension i use instructions of the loos gauge and 'mast tune' yamaha manual.

simon

 

[Syntonos]

Acronyms = Yank mis-communication method.

ATF - Automatic Transmission Fluid.

Don't have time to pull the chainplates for a couple of weeks. Initial silicone removal looks good. My boat may have had them replaced when it was upgraded to Dyform (swaged) rigging in 2000 before I bought it. I'm hoping thats the case.

In an earlier post you mentioned you may be in LA in the future- be sure to look me up!

Was curious about rig # as I may get back into competition and your the first to talk race with these old IOR war horses.

 

[siandimi]

my fellow Yamaha 25 owners and others(who is not strong enough should not read or look further!)

i cut the sylicone around chaine plate,found cracks,supported beam,dismantled chain plates,all is there for you to see!
because others have not reported something similar,here is my two bob worth....

causes: --- chloride stress corrosion cracking combined with weekly club racing(more pleasure then racing!)
---oxygen starvation---embeded in glass,combined with above,or

----because it sits up side down(in comparison with most of the other Yamahas)

With chainplates or other old lumps of critical structural metal, even if they look luvverly and shiny and new with no apparent rust, they may well be shot to pieces with micro cracks...

The only way to find out is to get them out and crack test them using a dye penetrant test kit available from your local welding suppliers or other hardware store. You get three cans in a test kit - a cleaner, dye and this weird chalky spray. Used properly, this dye kit will show whether the stainless has any cracks in it or not, and will therefore enable you to sail away more confident in your rig and sleep soundly through any typhoons / hurricanes that come your way...

S

 

[furdui]

ATF - Automatic Transmission Fluid.

Don't have time to pull the chainplates for a couple of weeks. Initial silicone removal looks good. My boat may have had them replaced when it was upgraded to Dyform (swaged) rigging in 2000 before I bought it. I'm hoping thats the case.

In an earlier post you mentioned you may be in LA in the future- be sure to look me up!

Was curious about rig # as I may get back into competition and your the first to talk race with these old IOR war horses.

I've installed new chain plates,30x5 mm,22 mm2 extra,I can get an extra tension in the rig!!

I've checked the rig tension,I have 210 kgf in upper shrouds,front and back stays,and when racing or heavier weather I'll increase the tension in backstay to approx. 260 kgf.For lower shrouds I used the method from owners manual,I don't have Loos&co for 2.5 to 4 mm.
Re racing,I mentioned,it is club racing and very enjoyable and nobody gets killed!!,and because there are different sizes and makes of yachts(some times we get over 40 boats),we have handicap start,my handicap is approx 35 min,but I have to say the 'old war horse' is quite competitive.

 

[Syntonos]

Thanks for the #'s Simon.
Now all I need to do is convert it to Yank language. I'll be doing the same ,PHRF handicap, if I decide to hop into a regatta or two. I too am becoming an Old war horse, just like my boat.
We seem to be digging up quite a few Y25's here in Southern California. 5 boats make a class here- you guys out there listening, Wouldn't that be a hoot !

40 boats is a great turn out. Here in the States there are so many Clubs with competing regattas on the same weekend that it thins out the heard with each boat supporting thier own club's event.

Sorry don't have any YSE8 info. by the way "E" indicates early , M-modern

best wishes

 

[furdui]

hi syntonos,

had no spare time,went through national parks--"rocky mountains frontiers"-- from denver down to la,4000 mls,first time on main land usa(been before in hawaii),you've got a great country!!


""In an earlier post you mentioned you may be in LA in the future- be sure to look me up!""

 

[Syntonos]

Visit to the States

Glad to here your trip was for pleasure and not buisness!
We tend to miss the opportunity to do the Living part while struggling to make a "living". Glad to here you havn't missed the boat on that point!

Just last year a friend and I motorcycle toured Colorado backroads crossing the continental divide no less than 5 times on backroads (dirt). - Spectacular! You made a good choice. Our earth is truly a jewel.