Saildrives?

[Sailorman Ed]

Seaking - do you have a picture to post? So I assume that with the tank higher, you are essentially over-filling the oil?

Mark - I have seen the rubber hub on outboards but had never thought about being electrically isolated - I am always learning.

Going up to my boat Friday and will find out what model of Yanmar drive I have. This thread has been very helpful to me.
Ed

[dennisail]

My SD20s have 1500 hours and the seals have worn grooves into the shafts. I was able to linish most of it away.

I like the header tank idea. So that oil leaks out rather than water leaks in. Will the sail drive operate OK with the slight oil pressure and 100% full oil that this will cause?

[SeaKing]

I still change the seals at haul out , but in case there is a problem the positive pressure should stop the minor inflow of water. Oh, and yes the gear box is overfilled. No pictures and the boat is several hours away from me, out of the water untill no nite time freezing. I have both prop shafts and gear sets pulled out to change the seal on each shaft.

I have had no water issues since I installed the "header tank"

[SeaKing]

I just found out today that ZF has a drive that yanmar is now using as their SD60, they just repaint and label. This is from a source that manages a fleet of sail drive cats. No cone clutches in the SD 60.

My older SD31 drives have a dog clutch , much more reliable

[SeaKing]

Originally Posted by Sailorman Ed

Seaking - do you have a picture to post? So I assume that with the tank higher, you are essentially over-

Going up to my boat Friday and will find out what model of Yanmar drive I have. This thread has been very helpful to me.
Ed

The older SD 20's and the 31 have the dog clutches, what size engines do you have? 39HP and above use the SD31 or the newer SD 50 with the cones. Our older boat is a 1997 , I am not sure when the 50's came on the market

[dennisail]

Any tips on getting the boots to stick to to the hull?

After a lot of effort mine have come loose. I got brand new ones. I sanded the antifoul right back and epoxied the hull in the area so sikaflex would have something good to stick to, and it did, but the sika did not hold on the rubber boots and they are now hanging back down in front of the props.

Whats the fix for this and can it be done between tides?

[Schmacko]

Use Bostik Xtreme Seal and Fix it is nearly as good as Simpsons but not as expensive....but definately better than Sika....I stock all three but Bostik is is nore than capable of the job

[dennisail]

Thanks! Anyone know where to get it in AU?

[DotDun]

Originally Posted by dennisail

Any tips on getting the boots to stick to to the hull?

After a lot of effort mine have come loose. I got brand new ones. I sanded the antifoul right back and epoxied the hull in the area so sikaflex would have something good to stick to, and it did, but the sika did not hold on the rubber boots and they are now hanging back down in front of the props.

Whats the fix for this and can it be done between tides?

Screws into the hull.

I had composite cover fabricated (maybe 1/8" thick) and screwed to the hull.

[Cotemar]

Just use contact cement like the original factory install

[hugosalt]

Originally Posted by dennisail

Any tips on getting the boots to stick to to the hull?

After a lot of effort mine have come loose. I got brand new ones. I sanded the antifoul right back and epoxied the hull in the area so sikaflex would have something good to stick to, and it did, but the sika did not hold on the rubber boots and they are now hanging back down in front of the props.

Whats the fix for this and can it be done between tides?

After years of problems with boots on my SD 20
was told by knowledgeable oldtimer to use
BoatLife/Life Seal. Have had same one on for at least
six years now, no problem. A true pleasure! Thinking that Life Seal cures even better underwater.

[colemj]

DotDun has the answer. I have met more people with failed contact cement and Life Seal and 5200 solutions than I have met having success with these methods. The only universally successful method I have seen is to make a rigid cover plate and screw it into the hull.

Mark

[Sailorman Ed]

I took some pictures last weekend but do not see any nameplate. Can anyone tell me which model I have just from these pictures?

[ggray]

Originally Posted by DotDun

I'm not convinced the 'header tank' is a solution to the issue. As the lip seal wears the prop shaft it can't seal as well as when the shaft is new, hence water intrusion. IMO, the intrusion happens due to the drive case being sealed, it heats up during use creating a positive pressure, then when it cools down it creates a vacuum, and that is when it sucks water past the seal/worn shaft. This makes me think simply venting the drive would stop the pressure/vacuum situation. Drill a small hole (1/8"?) in the plastic cap and keep the oil level within range on the dipstick. This would allow for air movement, but oil shouldn't get high enough to leak. If in fact the shaft is worn such that water can get past the seal while in storage (no temperature swings), then it's time to address the worn shaft (replace or speed-sleeve).

Just my opinion!

Venting as you describe would probably be better than the original setup, but could get messy if the oil is pushed out. This seems to happen in cold weather. But you will still have less pressure inside the saildrive than the water pressure outside against the seals. With the header tank, in effect, the saildrive will be vented, plus by having the tank maybe a foot above the waterline, there will be slightly more pressure inside than out.

I have been using this system for about 10 years now I guess.

[dennisail]

Yeah I think the header tank has all the advantages of venting and more. The sail drives do seem to build up pressure. When I opened the suspect one of mine with the water in it (cold) it was actually under pressure and oil spewed out the filler! I can only assume water somehow got in and could not get out.