380: Sail Drive Bolts

[Cheyne]

We had do do a repower on our 380 and we are near the end, but we have a probelm with the bolts holding the sail drives in. The old bolts were really bad when they came out and now new bolts are not snugging down. By hand they are tight, but with a wrench they spin. Does anyone know if the bolt holes had glassed in metal thread or did they tape the fiberglass?

Cheyne

[skipperpete]

Originally Posted by Cheyne

We had do do a repower on our 380 and we are near the end, but we have a probelm with the bolts holding the sail drives in. The old bolts were really bad when they came out and now new bolts are not snugging down. By hand they are tight, but with a wrench they spin. Does anyone know if the bolt holes had glassed in metal thread or did they tape the fiberglass?



Cheyne

I’m assuming your 380 had Yanmar saildrives and the standard Yanmar bed had a steel armature that the bolts screwed into. What engine/Saildrive did you repower with? If it’s a techno drive Saildrive be really careful about getting the bed surface perfectly flat for the puny sealing ring on the diaphragm. The yanmar SD had a big fat sealing edge moulded on the underside of the diaphragm and it was difficult to pull the alloy rim down to the fibreglass bed but they never leaked....... the techno’s are very unforgiving and will leak if there’s any imperfection on the bed. Often it’s wise to install a 10mm alloy spacer over the original fibreglass surface with a layer of 5200 between the two.

[Cheyne]

Originally Posted by skipperpete

I’m assuming your 380 had Yanmar saildrives and the standard Yanmar bed had a steel armature that the bolts screwed into. What engine/Saildrive did you repower with? If it’s a techno drive Saildrive be really careful about getting the bed surface perfectly flat for the puny sealing ring on the diaphragm. The yanmar SD had a big fat sealing edge moulded on the underside of the diaphragm and it was difficult to pull the alloy rim down to the fibreglass bed but they never leaked....... the techno’s are very unforgiving and will leak if there’s any imperfection on the bed. Often it’s wise to install a 10mm alloy spacer over the original fibreglass surface with a layer of 5200 between the two.

We are putting in SD60’s with 3JH40’s. Seal isn’t a problem. Two of the bolt holes were so gubered up by the last owner when he had the SD20’s out. They put a impact on it and kept going until it was all the way in. We ended up drilling the hole out and retapping with a M10 instead of the M8 that was there.

Cheyne

[skipperpete]

Thanks for the update, well done tapping out the damaged holes. Were your SD 60’s supplied with the stainless steel spacer kit to accommodate the rear mount?

[Cheyne]

They didn't supply them. Instead the yard made mounts for the rear. Outside of the stripped bolts the install went pretty easy.

Cheyne

[Scubaseas]

Originally Posted by Cheyne

We are putting in SD60’s with 3JH40’s. Seal isn’t a problem. Two of the bolt holes were so gubered up by the last owner when he had the SD20’s out. They put a impact on it and kept going until it was all the way in. We ended up drilling the hole out and retapping with a M10 instead of the M8 that was there.

Cheyne

Helicoil is a good way to address stripped bolts. Especially stainless bolts into aluminum alloy holes. Use loctite 242 on the helicoil insert and anti-seize or tefgel on the bolt and you can actually remove and reuse the bolt 5 years later. Going oversize of course works too.