Archive | October, 2013
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300 Ton Travel Lift and the Roter Sand

29 Oct

300 Ton Travel Lift and the Roter Sand

This 300 Ton travel lift made short work of hauling and launching the Roter Sand. Expert and efficient service at Riviere au Renard, Gaspe

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Better Hose Clamps

29 Oct

I often see situation on either exhaust hose or stuffing boxes where there is not enough space on the hose to double clamp. Most small vessels use ordinary screw type hose clamps and if the screw loosens or strips there can be a serious risk of water getting in.

T-bolt type hose clamps are much more resistant and are a reasonable solution when only one hose clamp can be set.

 

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Galvanic Isolators

11 Oct

As seen on a three year old sport cruiser this past week, these Bravo three outdrives have corroded in a significant fashion while being immersed in fresh water. This is not a normal amount of corrosion particularly since the drives are well protected by anodes. 

This is more  likely a result of boats being connected together through the marina shore power grounding wire which allows current to flow between them more easily. 

The solution for this is a Galvanic Isolator on the ground wire just inboard of the shore power dual pole breaker. Easy to wire up and will save you a lot of money down the line. The isolator blocks low amperage current associated with galvanic corrosion but will open up the conductor ( close the circuit) if there is short to ground.

Learn more at http://www.sterling-power.com/products-galvanic-why.htm

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Blocking Problems on Older Cruiser

10 Oct

Interesting case a little while ago of a late 70’s 34 foot cruiser which was up on stands for a season or two. The hull was supported at three points: The aft corners on the chines and forward just aft of the stem. As can be seen in the photo, the surface of the block supporting the front was too small and eventually the blocks passed right through the hull. 

I think there are a couple of interesting things here. 1- The yard assumed that the structure was designed to handle a point load as is the case on most modern cruisers, but this vessel only has the hull shell to support the load. No keel or back bone and no local reinforcement. 2- The hull is made with a balsa core which delaminated long ago. So the already weakened structure did not stand a chance.

Although there are two 6×6 timbers below the keel, there was in fact only one at the time of the collapse. Note to owners of older cruisers: make sure the hull is supported on a sufficient number of blocks so the pressure on the shell is minimized.

 

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