J/22 Klassenvereinigung Deutschland » Suche/Biete » Biete » Was man beim Kauf einer gebrauchten J22 beachten sollte
#1 Was man beim Kauf einer gebrauchten J22 beachten sollte von Thomas Hanf
07.09.2011 08:07
Was man beim Kauf einer gebrauchten J22 beachten sollte:
Die Unterschiede zwischen italienischen und südafrikanischen Booten liegen eher im Detail, wie z.B.
- Fenster in Alurahmen (Italien) oder Plexiglas aufgesetzt (Südafrika)
- Wartungsluken achtern innen (Italien) oder außen oben (Südafrika)
Vom Grundsatz ist zu sagen, daß die südafrikanischen Boote älter sind, da die Produktion in Italien noch nicht so lange läuft und vorher die Boote aus Südafrika nach Europe importiert wurden.
Weder von der Wettbewerbsfähigkeit noch von der Haltbarkeit gibt es Unterschiede zwischen den verschiedenen Werften. Nach Mitte der 90'er Jahre wurden kaum noch südafrikanische Boote importiert. Daher sind die meisten angebotenen Boote nach diesem Zeitpunkt aus italienischer Produktion.
Die älteren Schiffe beider Werften haben noch ein Holzschot und Holzbänke in der Kajüte. Die neueren Schiffe haben eine GFK-Schot und statt der Holzbänke zwei wasserdichte Staukästen auf denen man sitzen kann. Ich kenne derzeit kein südafrikanisches Boot das diesen neuen Innenausbau hat.
Wenn das Schiff keinen Unterwasseranstrich hat, was bei vielen Schiffen in Holland der Fall ist, muß man noch mit ca. 1500,- € für einen solchen rechnen.
Nachfolgend eine Zusammenstellung der wichtigsten Punkte auf die zu achten ist beim Kauf einer gebrauchten J/22:
1. Schott überprüfen
Hier ist darauf zu achten ob die Pütting-Beschläge dicht waren, da andernfalls Wasser in das Balsaholz des Decks, sowie das Sperrholz des Schotts eindringen kann und dieses aufweicht.
2. Überprüfen der Luft-Tanks
Es gibt zwei Lufttanks. Einer unter dem Cockpit und der andere im Vorschiffbereich. Beide sollten trocken sein
3. Deck/Rumpf Verbindung
Hier ist auf Wasserspuren zu achten, sollte aber vom Grundsatz her eher selten der Fall sein.
4. Deck rund um die Pütting-Beschläge
Hier ist der Bereich rund um die Pütting-Beschläge auf weiche Stellen zu prüfen. Falls ja steht eine Reparatur an.
5. Niedergangs-Abdeckung
Auch diese hat einen Balaholz-Kern und daher müssen die darauf angebrachten Beschläge gut abgedichtet angebracht werden. Falls nicht weicht das Balsaholz auf und die Beschläge können bei größerer Belastung ausbrechen.
6. Mast-Fuß
Hier ist auf Risse zu achten. Kleine Haar-Risse sind meist harmlos, aber größere Risse deuten auf ein Problem hin.
7. Heckbereich um die Ruderbeschläge
Auch dieser Bereich ist auf Risse zu überprüfen. Falls dort verstärkt Risse vorhanden sind, könnten diese auf ein Problem mit dem Balsakern schließen lassen
8. Kiel
Hier dürfen keine Risse zwischen Kiel und Rumpf vorhanden sein. Ansonsten deutet dies daraufhin, daß sich der Kiel etwas vom Rumpf gelöst hat was nach starker Grundberührung oder unsachgemäßen Auflagen am dem Trailer auftreten kann.
9. Großbaum
Die Haltepunkte für Großschot und Baumniederholer überprüfen ob die noch ordentlich fest sind. Ansonsten müssen diese ggf. mit größeren Schrauben neu befestigt werden.
10. Baujahr/Rumpfnummer
Die Rumpfnummer ist am Heck auf der Steuerbordseite eingeprägt. Da die Rumpfnummer immer fortlaufend vergeben wird, kann damit das Herstellungsjahr relativ sicher ermittelt werden. Eine leichte Verschiebung kann sich nur ergeben haben wenn die Herstellung des Rumpfes bei einer der drei Werften etwas verzögert erfolgte kann ein Schiff von einer anderen Werft mit einer höheren Baunummer früher hergestellt worden sein. Wie gesagt kann es sich hier aber nur um wenige Wochen handeln, ab er sicher nicht über mehrere Monate.
11. Osmosegefahr bei J22
Bei sorgfältiger Ausführung und entsprechender jährlicher Auffrischung sollte Osmose kein Thema sein. Grundsätzlich ist zu sagen, dass das Osmose-Risiko in Süsswasser höher ist als in Salzwasser und dass die Osmosegefahr bei höheren Wassertemperatur steigt. Eine warme Süsswasserpfütze somit ein deutlich höheres Risiko darstellt, wie ein Liegeplatz in der kalten Nordsee.
Bisher sind mir keine ernsthaften Osmoseschäden bei J/22 Schiffen bekannt geworden.
Check List for Buying Used J22's
By vic - Mo' Money on Thursday, March 23, 2006 - 12:46 pm:
I was asked what to look for in a used J/22, here are my thoughts. I've included this in the FAQ section to encourage others to add or dispute what I wrote. vic
As the the J/22 is a basic, small keelboat, it is a rather simple boat that lends itself to "Do It Yourself" projects. Many problems can be addressed DIY at far less cost than professional repairs. The price is time and often time’s hard work. This is not intended to be a boat survey course, just some info on possible J/22 issues.
1.) GENERAL
* Inspect the Bulkheads. If the chainplates have leaked, the water often soaks into the plywood bulkhead and deck balsa core. Indications of possible problems are: a soft feel in the bulkhead wood when pushed with a screwdriver or knife blade, and heavy grain cracks showing in the white paint. Check the area of the chainplate attachments proper and lower down also. The lower problems may be a result of the water wicking down the inside layers of plywood from the chainplates or standing water in the forward area, not necessarily that the boat was filled with bilge water. (See Desperado's This Old Boat site.) Minor chainplate problems can often be addressed by installing oversized clamp plates to increase the surface area and the number of fasteners.
* Check the Air Tanks. There are two floatation tanks. One forward under the vee berth. One aft under the cockpit sole. Remove the interior plastic deck plate covers and look for standing water. They should be dry. Check for indications of rot in the tank sides from long term standing water. Remove the outside aft tank deck plate (located under the tiller). This allows easy inpection of the rudder gudgeon plate bolts and back plates. It is not uncommon for leaks to develop around the gudgeon plate bolts. Water leaks here can soak up into, and rot, the transom balsa core.
* Look for Streaks Down the inside of the Hull. The toerail and flange bolts loosen over time and may leak. This is generally not a major problem as I don't believe the bolts penetrate the balsa core, just some information. I have found that tightening all the toerail and flange nuts will usually stop the leaks.
* Inspect the Deck around the Chainplate Covers. The deck is balsa cored. If the chainplates leaked, over time the balsa core can rot. Look for heavy stress cracks around the chainplate covers (spider cracks are common and generally not a problem), or spongy feel in the area.
* Inspect the Sea Hood. Improperly bedded hardware like cam cleats, fairleads, etc. can allow water into the balsa core. Check for spongy areas. Removing the sea hood and inspecting the underside for dark areas showing the rot may be necessary. (See Desperado's This Old Boat site.)
* Inspect the Mast Step. The mast plate should be properly bedded and bolted tight. Small spider cracks are common and not generally a concern. Heavy, deep cracks may indicate problems.
* Inspect the Transom Gelcoat. Cracks radiating out from the gudgeaon plates may indicate problems with the transom balsa core. Inspect the cockpit drain fittings for the same cracks indicating weakening from leaks there too.
* Inspect the Keel. Check for cracking along the keel sump to keel joint. Small spider cracks are not uncommon. A heavy obvious crack will require at the least tightening of the keel studs and repairing the joint.
* Inspect the Mainsheet and Vang Bales on the Boom. The threaded bolt end can saw thru the aluminum. This can enlarge the hole and weaken the extrusion.
RACING
* Check for a J/22 Class Measurement Certificate. If a boat has never been measured in, it can be quite a bit of work to get her to J/22 Class standards. A new certificate will be necessary, as it is not transferable to the new owner.
* A properly faired bottom, keel and rudder is a plus. (Notice I said "properly", not "professionally". It is possible for a non-professional to do a good job, but a reputable professional does add credibility.)
* Check for Bottom Paint. If you plan to seriously race in major J/22 One Design events, eventually you will want an unpainted bottom. Bottom paint removal can be done, but it is hard work.
* Don't worry about Racing Sails. You will need to buy some new sails for big events anyway. If there are good sails, that's a plus, but not a "must have".
* You don't want lifelines and pulpits. All the lifelines do is interfere with foresails and hit you in the lower leg to flip you overboard.
* Inspect the Traveler Hardware. If you plan to race, you probably won't be happy with the old Nico Fico hardware.
* You'll need a good trailer to travel.
Quelle: http://wyc.org/j22/StuffForSale/VicsBuyingTips/tabid/561/Default.aspx
Als PDF: http://www.j22.com/pdfs/Waterline_Keel_Bolts_Article.pdf
M a i n t e n a n c e B u l l e t i n
K e e l B o lt s
Keel Bolt Maintenance Bulletin
There aren’t many maintenance areas that are more important, or more often overlooked than keel bolts. This is true for every boat, but particularly so for J/22s, J/24s and J/80s, all of which routinely hoist the boats in and out of the water using the bolts.
Failure of any keel bolt is bad, but most bolts are part of a massively redundant system, where the failure of any one bolt is rarely immediately catastrophic. For boats that are hoisted, the failure of a bolt holding the lifting gear can be catastrophic and has the potential to lead to the loss of the boat, or much, much worse.
While this article is being distributed to USWatercraft and J/Boats customers, it applies to virtually all production boats, regardless of builder or brand. If they use Stainless Steel keelboats and most of them do, it applies. Feel free to pass it along to your friends and fellow boat owners. It’s pretty important.
Since they live in the bilge, keel bolts can fall into the category of “out of sight, out of mind”. It is because they live in the bilge that they need routine care and attention.
J/22 keels are made using 316 Stainless Steel threaded rod, which is cast into the lead. The nuts, washers and lifting bar are made using 304 Stainless and are then electro polished. This has been the industry standard for many years, and has provided many years of service life.
Stainless Steel is corrosion resistant, not corrosion proof
The basic resistance of stainless steel occurs because of its ability to form a protective coating on the metal surface.
This coating is a "passive" film, which resists further "oxidation" or rusting. The formation of this film is instantaneous in an oxidizing atmosphere such as air, water, or other fluids that contain oxygen. Once the layer has formed, we say that the metal has become "passivated" and the oxidation or "rusting" rate will slow down to less than 0.002" per year (0,05 mm. per year).
Unlike aluminum or silver this passive film is invisible in stainless steel. It's created when oxygen combines with the chrome in the stainless to form chrome oxide, which is more commonly called "ceramic". This protective oxide or ceramic coating is common to most corrosion resistant materials. Unfortunately Halogen salts, especially chlorides easily penetrate this passive film and will
allow corrosive attack to occur.
CONCENTRATED CELL OR CREVICE CORROSION
This corrosion is common between nut and bolt surfaces. Salt water applications are a severe problem because of the salt water’s
low PH and its high chloride content. Here is the mechanism:
• Chlorides pit the passivated stainless steel surface.
• The low PH salt water attacks the active layer that is exposed.
The absence of oxygen inhibits the re-forming of the passive layer.
These three factors work together in a vicious cycle, repeatedly attacking the same small area. If the metal is under tensile stress- like from an over torqued keel bolt nut, the pit formed can transform itself into a crack. When a crack forms the process repeats and accelerates as the surface area of the ‘active’ layer is now much larger.
Prevention is the best cure
The best way to prevent corrosion is to keep salt away from your bolts. The best way to do that is to keep your bilge clean and dry. We’ve designed our interiors to be easily washed down. Take advantage of this. At the end of the day, when you hose off your deck hardware, stick the hose down the companionway and blast out the bilge and bolts. Pump and sponge dry and leave the floorboard off when you leave. Not only will this protect your keel bolts from corrosion, it will prevent mildew and keep your interior looking and smelling fresh.
Important note! Avoid using any cleaning products containing chlorine. Chlorides are just what we are avoiding. Read the label. Clorox, Comet, and Fantastic are all products that while good for most stuff are bad for this application. Check the label.
Annual Maintenance
Checking your keel bolts should be part of your annual maintenance plan. Working one bolt at a time, remove the nut and washer and clean the
threads with a small nylon or brass brush or scotch brite. Do not use a steel wire brush, as this can lead to other corrosion issues not covered here!
Check for signs of rust. If everything looks good, use a generous coating of anti-galling compound and re-torque the nut. Most J/22 keel bolts are 5/8
Keel Bolt Torque Table
Tip- If you can pull in your mainsheet, you probably don’t need a big breaker bar to torque your nuts. Over-torqueing is extremely bad. Particularly on the bolts holding your lifting rig, under-torqueing is equally bad. If the nut is loose enough to allow movement in the bar, the bolt can be
loaded unequally, leading to tension stress on one side of the bolt.
While you are there
Since you are spending some time with your bilge anyway, this is a good time to give the rest of your lifting gear a good look over. Check your sling for any signs of wear; fraying, cuts, abrasions and the like. Your sling should look essentially new.
If you use a shackle in your system, check it too. If it is bent, rusted or shows signs of wear, just replace it. A new sling costs around 50 bucks and a shackle around 9 bucks. It is the cheapest peace of mind available.
If you think you find a problem If you find or suspect you have problems beyond a good cleanup you should contact a marine surveyor who can inspect and report findings. Your surveyor will have the specialized knowledge and tools to give you an informed recommendation.
Bolt Diameter Torque Nm Torque Ft/Lb
1/2" 26.0 19.2
5/8" 66.0 48.7
3/4" 130.0 95.9
7/8" 190.0 140.1
This Table is derived from information in Table A7 from ISO/DIS
12215?9.2. These values are for well greased threads. Friction in the
screw and under the bolt head makes up approximately 90% of the
tightening torque and approximately 10% contributes to prestress?
ing of the bolt. The user is cautioned to use good judgment in apply?
ing these values.
Additional Resources
Lots of info on Stainless http://www.azom.com/article.aspx?ArticleID=1177#_Background
Info on galvanic corrosion
http://www.corrosionist.com/Galvanic_Series_of_Metal_in_Seawater.htm
Recommended Anti-Galling compound
Loctite(R) Marine Grade Anti-Seize available @ Amazon and a gajillion other places
http://www.amazon.com/16-Oz-Marine-Grade-Anti-seize/dp/B0042T5MS0/ref=pd_sbs_indust_4
Lifting Strap:
http://www.waterlinesystems.net/servlet/the-208/Lifting-Strap%2C-Web-2x5%2C/Detail
Die Unterschiede zwischen italienischen und südafrikanischen Booten liegen eher im Detail, wie z.B.
- Fenster in Alurahmen (Italien) oder Plexiglas aufgesetzt (Südafrika)
- Wartungsluken achtern innen (Italien) oder außen oben (Südafrika)
Vom Grundsatz ist zu sagen, daß die südafrikanischen Boote älter sind, da die Produktion in Italien noch nicht so lange läuft und vorher die Boote aus Südafrika nach Europe importiert wurden.
Weder von der Wettbewerbsfähigkeit noch von der Haltbarkeit gibt es Unterschiede zwischen den verschiedenen Werften. Nach Mitte der 90'er Jahre wurden kaum noch südafrikanische Boote importiert. Daher sind die meisten angebotenen Boote nach diesem Zeitpunkt aus italienischer Produktion.
Die älteren Schiffe beider Werften haben noch ein Holzschot und Holzbänke in der Kajüte. Die neueren Schiffe haben eine GFK-Schot und statt der Holzbänke zwei wasserdichte Staukästen auf denen man sitzen kann. Ich kenne derzeit kein südafrikanisches Boot das diesen neuen Innenausbau hat.
Wenn das Schiff keinen Unterwasseranstrich hat, was bei vielen Schiffen in Holland der Fall ist, muß man noch mit ca. 1500,- € für einen solchen rechnen.
Nachfolgend eine Zusammenstellung der wichtigsten Punkte auf die zu achten ist beim Kauf einer gebrauchten J/22:
1. Schott überprüfen
Hier ist darauf zu achten ob die Pütting-Beschläge dicht waren, da andernfalls Wasser in das Balsaholz des Decks, sowie das Sperrholz des Schotts eindringen kann und dieses aufweicht.
2. Überprüfen der Luft-Tanks
Es gibt zwei Lufttanks. Einer unter dem Cockpit und der andere im Vorschiffbereich. Beide sollten trocken sein
3. Deck/Rumpf Verbindung
Hier ist auf Wasserspuren zu achten, sollte aber vom Grundsatz her eher selten der Fall sein.
4. Deck rund um die Pütting-Beschläge
Hier ist der Bereich rund um die Pütting-Beschläge auf weiche Stellen zu prüfen. Falls ja steht eine Reparatur an.
5. Niedergangs-Abdeckung
Auch diese hat einen Balaholz-Kern und daher müssen die darauf angebrachten Beschläge gut abgedichtet angebracht werden. Falls nicht weicht das Balsaholz auf und die Beschläge können bei größerer Belastung ausbrechen.
6. Mast-Fuß
Hier ist auf Risse zu achten. Kleine Haar-Risse sind meist harmlos, aber größere Risse deuten auf ein Problem hin.
7. Heckbereich um die Ruderbeschläge
Auch dieser Bereich ist auf Risse zu überprüfen. Falls dort verstärkt Risse vorhanden sind, könnten diese auf ein Problem mit dem Balsakern schließen lassen
8. Kiel
Hier dürfen keine Risse zwischen Kiel und Rumpf vorhanden sein. Ansonsten deutet dies daraufhin, daß sich der Kiel etwas vom Rumpf gelöst hat was nach starker Grundberührung oder unsachgemäßen Auflagen am dem Trailer auftreten kann.
9. Großbaum
Die Haltepunkte für Großschot und Baumniederholer überprüfen ob die noch ordentlich fest sind. Ansonsten müssen diese ggf. mit größeren Schrauben neu befestigt werden.
10. Baujahr/Rumpfnummer
Die Rumpfnummer ist am Heck auf der Steuerbordseite eingeprägt. Da die Rumpfnummer immer fortlaufend vergeben wird, kann damit das Herstellungsjahr relativ sicher ermittelt werden. Eine leichte Verschiebung kann sich nur ergeben haben wenn die Herstellung des Rumpfes bei einer der drei Werften etwas verzögert erfolgte kann ein Schiff von einer anderen Werft mit einer höheren Baunummer früher hergestellt worden sein. Wie gesagt kann es sich hier aber nur um wenige Wochen handeln, ab er sicher nicht über mehrere Monate.
11. Osmosegefahr bei J22
Bei sorgfältiger Ausführung und entsprechender jährlicher Auffrischung sollte Osmose kein Thema sein. Grundsätzlich ist zu sagen, dass das Osmose-Risiko in Süsswasser höher ist als in Salzwasser und dass die Osmosegefahr bei höheren Wassertemperatur steigt. Eine warme Süsswasserpfütze somit ein deutlich höheres Risiko darstellt, wie ein Liegeplatz in der kalten Nordsee.
Bisher sind mir keine ernsthaften Osmoseschäden bei J/22 Schiffen bekannt geworden.
Check List for Buying Used J22's
By vic - Mo' Money on Thursday, March 23, 2006 - 12:46 pm:
I was asked what to look for in a used J/22, here are my thoughts. I've included this in the FAQ section to encourage others to add or dispute what I wrote. vic
As the the J/22 is a basic, small keelboat, it is a rather simple boat that lends itself to "Do It Yourself" projects. Many problems can be addressed DIY at far less cost than professional repairs. The price is time and often time’s hard work. This is not intended to be a boat survey course, just some info on possible J/22 issues.
1.) GENERAL
* Inspect the Bulkheads. If the chainplates have leaked, the water often soaks into the plywood bulkhead and deck balsa core. Indications of possible problems are: a soft feel in the bulkhead wood when pushed with a screwdriver or knife blade, and heavy grain cracks showing in the white paint. Check the area of the chainplate attachments proper and lower down also. The lower problems may be a result of the water wicking down the inside layers of plywood from the chainplates or standing water in the forward area, not necessarily that the boat was filled with bilge water. (See Desperado's This Old Boat site.) Minor chainplate problems can often be addressed by installing oversized clamp plates to increase the surface area and the number of fasteners.
* Check the Air Tanks. There are two floatation tanks. One forward under the vee berth. One aft under the cockpit sole. Remove the interior plastic deck plate covers and look for standing water. They should be dry. Check for indications of rot in the tank sides from long term standing water. Remove the outside aft tank deck plate (located under the tiller). This allows easy inpection of the rudder gudgeon plate bolts and back plates. It is not uncommon for leaks to develop around the gudgeon plate bolts. Water leaks here can soak up into, and rot, the transom balsa core.
* Look for Streaks Down the inside of the Hull. The toerail and flange bolts loosen over time and may leak. This is generally not a major problem as I don't believe the bolts penetrate the balsa core, just some information. I have found that tightening all the toerail and flange nuts will usually stop the leaks.
* Inspect the Deck around the Chainplate Covers. The deck is balsa cored. If the chainplates leaked, over time the balsa core can rot. Look for heavy stress cracks around the chainplate covers (spider cracks are common and generally not a problem), or spongy feel in the area.
* Inspect the Sea Hood. Improperly bedded hardware like cam cleats, fairleads, etc. can allow water into the balsa core. Check for spongy areas. Removing the sea hood and inspecting the underside for dark areas showing the rot may be necessary. (See Desperado's This Old Boat site.)
* Inspect the Mast Step. The mast plate should be properly bedded and bolted tight. Small spider cracks are common and not generally a concern. Heavy, deep cracks may indicate problems.
* Inspect the Transom Gelcoat. Cracks radiating out from the gudgeaon plates may indicate problems with the transom balsa core. Inspect the cockpit drain fittings for the same cracks indicating weakening from leaks there too.
* Inspect the Keel. Check for cracking along the keel sump to keel joint. Small spider cracks are not uncommon. A heavy obvious crack will require at the least tightening of the keel studs and repairing the joint.
* Inspect the Mainsheet and Vang Bales on the Boom. The threaded bolt end can saw thru the aluminum. This can enlarge the hole and weaken the extrusion.
RACING
* Check for a J/22 Class Measurement Certificate. If a boat has never been measured in, it can be quite a bit of work to get her to J/22 Class standards. A new certificate will be necessary, as it is not transferable to the new owner.
* A properly faired bottom, keel and rudder is a plus. (Notice I said "properly", not "professionally". It is possible for a non-professional to do a good job, but a reputable professional does add credibility.)
* Check for Bottom Paint. If you plan to seriously race in major J/22 One Design events, eventually you will want an unpainted bottom. Bottom paint removal can be done, but it is hard work.
* Don't worry about Racing Sails. You will need to buy some new sails for big events anyway. If there are good sails, that's a plus, but not a "must have".
* You don't want lifelines and pulpits. All the lifelines do is interfere with foresails and hit you in the lower leg to flip you overboard.
* Inspect the Traveler Hardware. If you plan to race, you probably won't be happy with the old Nico Fico hardware.
* You'll need a good trailer to travel.
Quelle: http://wyc.org/j22/StuffForSale/VicsBuyingTips/tabid/561/Default.aspx
Als PDF: http://www.j22.com/pdfs/Waterline_Keel_Bolts_Article.pdf
M a i n t e n a n c e B u l l e t i n
K e e l B o lt s
Keel Bolt Maintenance Bulletin
There aren’t many maintenance areas that are more important, or more often overlooked than keel bolts. This is true for every boat, but particularly so for J/22s, J/24s and J/80s, all of which routinely hoist the boats in and out of the water using the bolts.
Failure of any keel bolt is bad, but most bolts are part of a massively redundant system, where the failure of any one bolt is rarely immediately catastrophic. For boats that are hoisted, the failure of a bolt holding the lifting gear can be catastrophic and has the potential to lead to the loss of the boat, or much, much worse.
While this article is being distributed to USWatercraft and J/Boats customers, it applies to virtually all production boats, regardless of builder or brand. If they use Stainless Steel keelboats and most of them do, it applies. Feel free to pass it along to your friends and fellow boat owners. It’s pretty important.
Since they live in the bilge, keel bolts can fall into the category of “out of sight, out of mind”. It is because they live in the bilge that they need routine care and attention.
J/22 keels are made using 316 Stainless Steel threaded rod, which is cast into the lead. The nuts, washers and lifting bar are made using 304 Stainless and are then electro polished. This has been the industry standard for many years, and has provided many years of service life.
Stainless Steel is corrosion resistant, not corrosion proof
The basic resistance of stainless steel occurs because of its ability to form a protective coating on the metal surface.
This coating is a "passive" film, which resists further "oxidation" or rusting. The formation of this film is instantaneous in an oxidizing atmosphere such as air, water, or other fluids that contain oxygen. Once the layer has formed, we say that the metal has become "passivated" and the oxidation or "rusting" rate will slow down to less than 0.002" per year (0,05 mm. per year).
Unlike aluminum or silver this passive film is invisible in stainless steel. It's created when oxygen combines with the chrome in the stainless to form chrome oxide, which is more commonly called "ceramic". This protective oxide or ceramic coating is common to most corrosion resistant materials. Unfortunately Halogen salts, especially chlorides easily penetrate this passive film and will
allow corrosive attack to occur.
CONCENTRATED CELL OR CREVICE CORROSION
This corrosion is common between nut and bolt surfaces. Salt water applications are a severe problem because of the salt water’s
low PH and its high chloride content. Here is the mechanism:
• Chlorides pit the passivated stainless steel surface.
• The low PH salt water attacks the active layer that is exposed.
The absence of oxygen inhibits the re-forming of the passive layer.
These three factors work together in a vicious cycle, repeatedly attacking the same small area. If the metal is under tensile stress- like from an over torqued keel bolt nut, the pit formed can transform itself into a crack. When a crack forms the process repeats and accelerates as the surface area of the ‘active’ layer is now much larger.
Prevention is the best cure
The best way to prevent corrosion is to keep salt away from your bolts. The best way to do that is to keep your bilge clean and dry. We’ve designed our interiors to be easily washed down. Take advantage of this. At the end of the day, when you hose off your deck hardware, stick the hose down the companionway and blast out the bilge and bolts. Pump and sponge dry and leave the floorboard off when you leave. Not only will this protect your keel bolts from corrosion, it will prevent mildew and keep your interior looking and smelling fresh.
Important note! Avoid using any cleaning products containing chlorine. Chlorides are just what we are avoiding. Read the label. Clorox, Comet, and Fantastic are all products that while good for most stuff are bad for this application. Check the label.
Annual Maintenance
Checking your keel bolts should be part of your annual maintenance plan. Working one bolt at a time, remove the nut and washer and clean the
threads with a small nylon or brass brush or scotch brite. Do not use a steel wire brush, as this can lead to other corrosion issues not covered here!
Check for signs of rust. If everything looks good, use a generous coating of anti-galling compound and re-torque the nut. Most J/22 keel bolts are 5/8
Keel Bolt Torque Table
Tip- If you can pull in your mainsheet, you probably don’t need a big breaker bar to torque your nuts. Over-torqueing is extremely bad. Particularly on the bolts holding your lifting rig, under-torqueing is equally bad. If the nut is loose enough to allow movement in the bar, the bolt can be
loaded unequally, leading to tension stress on one side of the bolt.
While you are there
Since you are spending some time with your bilge anyway, this is a good time to give the rest of your lifting gear a good look over. Check your sling for any signs of wear; fraying, cuts, abrasions and the like. Your sling should look essentially new.
If you use a shackle in your system, check it too. If it is bent, rusted or shows signs of wear, just replace it. A new sling costs around 50 bucks and a shackle around 9 bucks. It is the cheapest peace of mind available.
If you think you find a problem If you find or suspect you have problems beyond a good cleanup you should contact a marine surveyor who can inspect and report findings. Your surveyor will have the specialized knowledge and tools to give you an informed recommendation.
Bolt Diameter Torque Nm Torque Ft/Lb
1/2" 26.0 19.2
5/8" 66.0 48.7
3/4" 130.0 95.9
7/8" 190.0 140.1
This Table is derived from information in Table A7 from ISO/DIS
12215?9.2. These values are for well greased threads. Friction in the
screw and under the bolt head makes up approximately 90% of the
tightening torque and approximately 10% contributes to prestress?
ing of the bolt. The user is cautioned to use good judgment in apply?
ing these values.
Additional Resources
Lots of info on Stainless http://www.azom.com/article.aspx?ArticleID=1177#_Background
Info on galvanic corrosion
http://www.corrosionist.com/Galvanic_Series_of_Metal_in_Seawater.htm
Recommended Anti-Galling compound
Loctite(R) Marine Grade Anti-Seize available @ Amazon and a gajillion other places
http://www.amazon.com/16-Oz-Marine-Grade-Anti-seize/dp/B0042T5MS0/ref=pd_sbs_indust_4
Lifting Strap:
http://www.waterlinesystems.net/servlet/the-208/Lifting-Strap%2C-Web-2x5%2C/Detail