While the boat is on the hard, I also will do the diaphragms as well as all the other seals on the SD50. I am concerned about the longevity of the SD50 as it's 17 years old with approximately 1600 hours on it. 

Given that the SD50 needs to be removed, I'm wondering if I should just replace the unit with the SD60 as I will already have incurred a lot of "sunk costs" associated with the switch. 

Would love to hear from those of you that have done so and how that has turned out?

• The SD60 has a different footprint and has two securing bolts at the aft end which are not on the SD50. You will need to ensure that you have the necessary metalwork in the bearers and holes drilled and tapped to take these bolts. My 2010 400 didn't so I had to buy an adaptor plate from Yanmar (just over £1,000). The plate also comes with plates for the engine mounts so that the whole engine is raised 12mm. This required new, longer M10 mounting bolts for both the SD60 and the engine mounts to bearers.
• You will need a new drive coupler plate for the engine. I couldn't source one in the UK or Europe but founds lots in the US ($400). 
• The gear selector lever is on the opposite side to the SD50, resulting in the throttle lever operating 'back to front' (ie. what was forward gear became astern!). I had to switch the gear cable to the other side of the throttle lever.
• The gear selector rubbed the exhaust hose, so I had to move that slightly.
• There is no space in the 400 aft of the saildrive so it cannot be tilted to the stern for removal - the 430 might be different. I had to split the SD50 in two for removal, with the leg removed from underneath and the transmission from the top. The SD60 needed the propshaft to be removed, which required the draining of the oil (it comes filled from the factory). I was then able to drop the SD60 in vertically (with engine removed).

Otherwise straightforward. Engine had to be removed completely and I needed to cut an additional access panel in the aft starboard cabin to enable alignment of the shaft to the saildrive.

Firstly, although the forums can be great there is a tendency for them to detail 'the sum of all fears'.  You read of the troubles others have had and understandably worry about your own situation.  Yet you'll never read about the far greater number of others that have never experienced the same malfunctions.  With specific regard to the SD50, yes; the cone clutch is a well known PIA that needs regular lapping - but there's a fix for that with the upgrade kit for about $750.  Mine has worked flawlessly for many hundreds of hours since upgrading and the available literature suggests this will extend the life of the clutch well beyond Yanmar's recommend for replacement at 2000 hours.  Even if you did replace the clutch, the cost isn't that great.  Much of my concern for my SD50 was a result of poor professional advice verging on the negligent.  I got a 2nd and confirmatory 3rd opinion and it turns out I needn't have worried at all.  Mine has now done 2000 hours and is running perfectly well.

My second point is the familiar 'if it ain't broke don't fix it'.  I went through a very similar thought-process to you so I understand your situation but if your SD50 is running fine - and given the option of the well-regarded upgrade kit - why go to all the hassle and expense that Martin has helpfully detailed?

With regard to the Silic 1, I changed to that 3 years ago after I had the SD leg epoxied as per Yanmar's recommendation; the difference was remarkable with much lower levels of fouling.  However, to put that in context, while Portsmouth Harbour is among the worst locations in the UK for heavy fouling we actively cruise for 5 months a year covering a lot of miles, so the way a boat is used might explain the disparity in the results you found.  

That all said, if you choose to save your money by not getting the SD60, your boat will soon figure out another way to reduce your bank balance by at least the same amount.

Good luck!

Iain

I have decided to keep the SD50 and refurbish the seals etc. and just stay on top of the maintenance. Also thinking I will source a spare lower leg that’s in good condition. 

Fingers crossed on the Silic One. 

Those hours include temporarily removing the exhaust hose and elbow as well as some of the plumbing associated with the hot water heater. 

Does that seem reasonable?

Hemorrhaging cash ….

Again - good luck!

On top of that were the yard costs for haul out, pressure washing, and re-blocking of the boat after the Silic One was applied to insure complete coverage of the hull. That came out to another $2700. These costs were higher as the cure times of the Silic One resulted in the boat being on the hard for 13 days @ ~$100/day. 

Anyone out there that has self performed the sd50 removal in a 430?

You'll need to separate the engine and transmission and slide the engine forward to allow the transmission to be lifted for the new diaphragms to be fitted. On the 400 it is much easier if the whole engine is removed but this needs a hoist etc. If the engine is removed you can remove the propshaft from the leg and lift the whole unit upwards and out without splitting it if preferred. 

Your quote appears high. Hours should be around 15-20 max and the hourly rate looks high. Although I ended up replacing the whole saildrive unit myself, the engineer I had previously booked for the diaphragm replacement had quoted £1,500 - 1-2 days work for two people. This included engine removal and refit. The exhaust hose and elbow needs to be removed (although I split the exhaust at the water trap and left the short house and elbow attached to the engine as this was easier). You also need to remove and plug the hot water calorifier hoses at the engine end. 

Last summer when I did the cone clutch "upgrade", (wondering how long that will last) there were 4 bolts that needed to be loosened but not removed - is their removal how one separates the engine and transmission? I found a manual online but it's not as detailed as I would like. Sounds like keeping the alignment of the pinion shaft is a big deal to avoid any "binding". Any tricks to suggest? 

Really appreciating the comments - keep them coming please. 

This shot might help. This is my SD50, inverted, & held on an engine house frame. The separation of the leg isn’t to tough. Just a case of creating access. On the 400e that means the engine slid forward to allow the upper portion of the drive to come out  vertically and upward while the leg is released downwards. I had professional help with this job so I won’t claim a DIY tick!  Does definitely help to have 2 people, one in the boat and one outside. 

Mark

I plan on removing the lower leg, then separate the engine, shift it and then remove the sail drive. 

Hopefully all goes well… 🤞🤞🤞

Any suggestions?

So the moral of the story is to clearly read and understand the manual (RTFM) and don’t force parts together. In my self defense, the manual I had sucks…. 

Did I mention that a boat can not only rejuvenate your soul, but also suck it out!

Hopefully you'll be able to get it all back together and back in the water soon.

I should also note that the diaphragms looked like they were brand new. What a crock replacing them at 7? years per Yanmar.

I contemplated replacing my SD50 with the SD60 last summer but opted not to. If I could go back in time, I would have done so as the costs that I incurred for new seals, repair of some bearings that I messed up etc would have contributed greatly to the cost of the new saildrive.