Sail drive Boots - Replacement Technique?

[pstadt]

I've removed our old boots (the external ones that are glued to the hull and surround the upper portion of the sail drive) and am prepping the area of the hull to receive the new ones.

I've been wanting to check on the condition of the saildrives that have been hidden by the boots so while JADE is up on the hard I decided to replace both boots. They've been on since construction (2011) and I have to say, they were really in pretty good shape, save for the minor tearing in the real soft sections that contacted the saildrives. The saildrives themselves look good, but can use a good barrier coat reapplication and some AF before I replace the boots.

In using some 5200 recently on the rudder shaft tube/external hull interface, I learned the hard way that 5200 doesn't set up very quickly (lots of it dripped right out of the fillet I was trying to create), so I'm skeptical about using it to glue the boots to the hull (overhead application).

Is there a better adhesive for attaching the sail drive boots?

Can anyone share their "new boot installation procedure"?

Thanks!

Pat

[belizesailor]

Youve had the original fairing seals in since 2011, wow! That must be a near record!
They dont usually last half that time.

Like many bonding jobs the key is in surface prep, sand the area on the hull to remove paint and rough up the surface a little, clean it well and let dry, similar with the fairing seal, rough it up a little with sandpaper to give a better grip. Apply adhesive to both sides and press into place. Ive used tape and various improvised supports (short sections of wood, scrap sheet material...whatever is laying around the boat yard...to hold the fairing skirt into place until the adhesive dries enough support it.

Ive always used 5200, apply to both surfaces and press together, roll out all voids, using the fast cure version helps.

I suspect that contact cemement would work quite well, and resolve the runny 5200 problem, but Ive not actually tried it.

However, Im quite happy to get a few seasons...the 6-7 youve gotten is exceptional. I would find out what the builder used!

[BlueChicago]

Perhaps this will help:

https://www.youtube.com/watch?v=pwD0T9skkTE

[deadliest catch]

I peeled mine off to do a proper cleaning under the boots.The guy I hired to help me prep my bottom reinstalled my boots for me using 5200. It had plenty of time to dry but. Around 6 months later half of each side had peeled off.

I pulled the boat for some bottom work and planned to replace the old with new but. On my Lagoon 450 the boots are a hard plastic. I ordered replacement parts from Yanmar but. They were a thin wimpy rubber and they didn't fit. Too small.

I called the Fort Lauderdale Lagoon dealer who told me they didnt sell them and must be a custom item from Lagoon. I was told they would need to be custom cut to size from a local Starboard company.

I splashed the boat without replacing the boots. Im told its not critical to have them installed so I'll deal with it next haul. Anyone know where to buy new proper boots?

[belizesailor]

They are not critical, but do help with fairing and significantly reduce marine growth inside the recess around the drive leg.

Saildrives move some in use, thus the flexible rubber fairing skirt and bellows (the main seal). A firmer material like starboard doesnt seem like the ideal solution to me.

[deadliest catch]

I say Starboard and it certainly was a stiff plastic but it could of been another material similar. In reality the boot didnt butt up to the saildrive. There was prolly a half inch space between if memory serves but we know how that goes.

The official Yanmar boots were definitely a soft flimsy rubber and I assumed what I originally pulled off was factory and maybe thats a wrong assumption. I wish I knew the correct facts.

[stormalong]

5200 cure can be accelerated by keeping it wet. After installation spray it with a spray bottle - water only. Whenever you are near it just hit it with the spray.

[chris in SG]

I replaced mine with rigid GRP sheet, about 2mm thick, which I laid-up myself (but you can usually buy for projects like fridge lining, etc). This is just thick enough to allow small countersunk screws to hold each piece in place. The gap between the rigid sheet and the saildrive is about 5mm, which is sufficient to avoid knocking.


No doubt some people would be horrified at the idea of screwing into the hull but in most cases a GRP hull will be solid laminate in this area and the screws only need to be long enough to hold the cover plates to the slightly curved hull section while sealant is bonding. I would not use 5200 because you want to be removing the covers during antifouling.

[belizesailor]

Originally Posted by deadliest catch

I say Starboard and it certainly was a stiff plastic but it could of been another material similar. In reality the boot didnt butt up to the saildrive. There was prolly a half inch space between if memory serves but we know how that goes[emoji3].



The official Yanmar boots were definitely a soft flimsy rubber and I assumed what I originally pulled off was factory and maybe thats a wrong assumption. I wish I knew the correct facts.

The originals from Volvo/Yanmar are soft rubber. The upside to the soft rubber is it can seal directly against the drive leg and thus more effectively close the cavity. A rigid material cannot.


The same company, ZF, builds the saildrives for both Volvo & Yanmar, but to slightly different specs/design, the Yanmar version seems more trouble prone than the Volvo version.

[Bean Counter]

On our 450F the boots are fiberglass and what ever the factory used was a real battle to get off. Used D bond and other methods and finally got them off. The sealant was so tough I used a grinder to get it off the top surfaces of the boots. After cleaning out the sail drive cavity I re-attached the boots with 4200 fast cure. After 3000nm they are still there, and hopefully easier to remove for next haul out.


I read on another post some where someone filled the cavity with expanding foam, but I would imagine that would be a tedious exercise to remove when required.

[LeeV]

Originally Posted by Bean Counter

On our 450F the boots are fiberglass and what ever the factory used was a real battle to get off. Used D bond and other methods and finally got them off. The sealant was so tough I used a grinder to get it off the top surfaces of the boots. After cleaning out the sail drive cavity I re-attached the boots with 4200 fast cure. After 3000nm they are still there, and hopefully easier to remove for next haul out.


I read on another post some where someone filled the cavity with expanding foam, but I would imagine that would be a tedious exercise to remove when required.

As a newbie to diesels and sail drives, I'm curious about the fiberglass boots with which I'm not familiar. Were the drives completely clean when you removed them? In other words could you see a huge improvement over standard boots?

Regards,

[Thumbs Up]

I use expanding foam then skin over it with 5200. The first time I used a lot of foam (pretty much filled the cavity) it is easy to remove, the stuff in the aerosol can is very low density. The last time I did it I made a plastic "mold" from an old jug that I propped up while the foam set. This way I didn't have to trim the foam back. Then I just squirted in a little foam. The problem with too much foam is that it increases vibration. Once the foam sets, pop off the plastic then prep the perimeters (the hull and saildrive leg) with sandpaper and masking tape and smear on 5200 (or any polyurethane sealant). Tool it so that it is reasonably smooth. Pull the tape and you are good to go. I think that next time I will add a layer of screen mesh to reinforce the caulk membrane. Make sure that you have a good inch of bonding width on the hulls (between where the foam ends and the masking tape). The foam is there mostly to give you something to tool the sealant onto but in the event of a seal rupture could also slow the flow of seawater coming in. If you can find a low enough density foam (the stuff that you spray around house window frames) it wouldn't hurt to fill the entire cavity as a safety precaution but like I said, I noticed an increase in vibration when I tried it the first time.

[Bean Counter]

Originally Posted by LeeV

As a newbie to diesels and sail drives, I'm curious about the fiberglass boots with which I'm not familiar. Were the drives completely clean when you removed them? In other words could you see a huge improvement over standard boots?

Regards,

There is a few mm gap between the fiberglass boot and the drive. Sea creatures still go in there. Our boots had not been removed for some years. There were oysters, crabs, and other sea life in there. When it was all cleaned off the drive legs themselves were in good condition with original paint. I inspected the rubber drive hull seals that were also in very good condition, then painted the inside of the cavity with Trilux 33 and glued the boots back on with 4200 so they hopefully come off easier next time. I don't know if it is any better than a rubber boot, I just heard that the rubber boots fall off sometimes.

[admiralslater]

On our Outremer we put a FIBERGLAS plate over the membrane, lots pf boats do this in the Caribbean

[LeeV]

Thanks for the explanations; I appreciate learning something new!

Regards,