What you are saying doesn't seem to make sense to me. From your description there seems to be water in the oil
. Is that correct? The hull seals do not have anything to do with water in the oil
. There are basically four places water can get into the sail drive oil, the oil drain screw, the prop shaft seals, the bearing carrier O-rings, and the O-rings between the lower housing and upper housing. The screw O-ring, prop shaft seals and bearing carrier O-rings can be easily serviced without removing the sail drive assuming the boat
is out of the water.
If I have misunderstood and you are talking about water between the hull seals then the drives do have to be removed. Keep in mind that the hull seals do not typically seal to the hull, but to the engine bed
. This is typically a pretty robust piece of structure not typically subject to warping and is typically located a couple of inches above the exterior hull opening. As Dulcesuenos pointed out the outer lip seal is simply to reduce hull drag from the sail drive opening and keep marine
growth out of the cavity between the sail drive bed
and the outer hull. It is not water tight. The dual hull seals located at the bed are meant to be water tight and may have in fact failed, but they have no connection to the inside of the sail drive and will not cause water to enter the oil. If the primary hull seal fails you will get water between the primary and secondary hull seals and the seal failure alarm
will go off. Do you test this detector as recommended in the user manual? If you don't it may have failed and not go off if the primary seal has failed. If you remove the sensor it will be apparent if the primary has failed as there will be water between the primary and secondary seals.
If there is water in the oil and no water between the primary and secondary seals then run, don't walk away from this mechanic, as he seems to be diagnosing your bank account rather than your sail drives.