Sonic saildrive - can someone explain ?

[pragmatist]

Looking at a boat which has a pair of Sonic sail drives and have been told they do not have a rubber seal they are direct mounted to the hulls. Since we are complete neophytes when it comes to saildrives rather confused. Thought all saildrives had seals which had to be replaced - every 7 years according to some insurers.

Can someone help me understand ?

Penny

 

[VicS]

Looking at a boat which has a pair of Sonic sail drives and have been told they do not have a rubber seal they are direct mounted to the hulls. Since we are complete neophytes when it comes to saildrives rather confused. Thought all saildrives had seals which had to be replaced - every 7 years according to some insurers.

Can someone help me understand ?

Penny

Mounted directly in the hull but you dont say if they are Mk 1 or Mk 2, catamaran drives or hydraulic drives. Whichever Google will find the info you seek including operators manuals.

 

[pragmatist]

Thanks Vic. I don't have a lot of information so putting 2 and 2 together. It is a catamaran (Prout 37) born in 1984 and my understanding is that the engines/stern gear are original so Mk I is the most likely. The engines are Yanmar 3HM. The spec does say "Sonic saildrives" and these, with catamaran sail drives and hydraulic drives are each listed separately. HWMBO has found a reference to cutting half to three quarter inch rubber (optional) and using mastic.

Still confused !

 

[RichardS]

Are they Sillette electric saildrives? These are bolted/bonded directly to the hull, presumably because of the lack of any vibration.

Richard

 

[voyager35]

my Mk 2 legs bolt onto the back of the engine pods and have a long o ring type seal glued into a channel that runs round near to the edge of the mounting plate to stop water getting into the engine bay. they are not a service item and should not need replacing unless damaged
Jonathan

 

[voyager35]

All the information ,Manuel's etc available on the sillette sonic website
Jonathan

 

[VicS]

Are they Sillette electric saildrives? These are bolted/bonded directly to the hull, presumably because of the lack of any vibration.

Richard

He says Yanmar 3HMs

The sail drive is bolted to a mounting pad or GRP plinth. The engine is mounted via its normal feet on to bearers. The two are connected with a flexible coupling.

 

[RichardS]

He says Yanmar 3HMs

The sail drive is bolted to a mounting pad or GRP plinth. The engine is mounted via its normal feet on to bearers. The two are connected with a flexible coupling.

Ah ... so it's the flexible coupling which removes the vibration and allows the solid mounting of the saildrive. Not a system I've ever come across.

Richard

 

[VicS]

Ah ... so it's the flexible coupling which removes the vibration and allows the solid mounting of the saildrive. Not a system I've ever come across.

Richard

Id not heard of it before either

If you think about it it is not dissimilar to an engine and shaft drive. Stern tube fixed to the boat hull, engine sitting on flexible feet on bearers . A flexible coupling between the two

 

[TQA]

Be aware that most if not all varieties of the Sonic drive legs require regular maintenance [ annual ] and if this is neglected the legs soon require expensive and extensive repairs.

https://www.boats.com/reviews/all-about-saildrives/

Spares are available.

I would ask the sellers