How many mark keel points ? For lifter guidance ?

[LittleSister]

The lifter does not need slings 'tied' to each other as guy can alter distance between them on the top rail .

Look at your lower photo graph, and think what will happen if that forward sling should start sliding up the curve of the hull towards the bow.

There is nothing to constrain the bottom of that sling moving forward, because the point of attachment of the sling is high above the hull - the sling itself would just as happy at say 45 degrees to the vertical.

Don't worry too much, though. It will be fine on most occasions.

 

[Refueler]

Look at your lower photo graph, and think what will happen if that forward sling should start sliding up the curve of the hull towards the bow.

There is nothing to constrain the bottom of that sling moving forward, because the point of attachment of the sling is high above the hull - the sling itself would just as happy at say 45 degrees to the vertical.

Don't worry too much, though. It will be fine on most occasions.

The sling you assume will have a vertical angle .... but operator can set the slings spacing so they actually can angle and reduce slippage ...

In over 50yrs of boating - never seen slings tied to each other yet ...

 

[Chiara’s slave]

The sling you assume will have a vertical angle .... but operator can set the slings spacing so they actually can angle and reduce slippage ...

In over 50yrs of boating - never seen slings tied to each other yet ...

Nor me. That arrangement must enable the slings to be as near as possible to 90 degrees to the surface they bear on, which must be best in every way mechanically. We’ll be lifting much of the Yarmouth XOD fleet in a few weeks. That is done with a crane, the slings naturally angle themselves with a single point of attachment. For those without their own strops that is.

 

[Stemar]

The yard tied the slings together when lifting Jazzcat recently. It really wasn't necessary, the barnacles provided a perfect non-slip surface

 

[LittleSister]

Nor me. That arrangement must enable the slings to be as near as possible to 90 degrees to the surface they bear on, which must be best in every way mechanically. We’ll be lifting much of the Yarmouth XOD fleet in a few weeks. That is done with a crane, the slings naturally angle themselves with a single point of attachment. For those without their own strops that is.

Tying them together just above deck height doesn't stop them being vertical (or 90 degrees as you put it), but it does stop them sliding up the curve and becoming non-vertical.

You and Refueler may not have seen (or perhaps noticed) it. But I have.

I've also seen it not done, and nearly lost my boat to it on one occasion. I'm sure you'll find other examples of its absence, too, among the 'boat lifting fails' on the internet.

 

[Buck Turgidson]

Depends on the boat and crane. In this case they couldn’t get the straps close enough for comfort so tied the strops together. I normally insist on it.

 

[penfold]

I have diver ready to do the job ... 70 euros includes full photographic stills / video .....

Or an amateur guy at 20 euro an hour ...

I have both HD Fishing camera and Endoscope .... problem then is as you say - positioning.

Being a modeller ... I have thought about getting one of those diving camera drones ....

Or you could pull the transducers.

 

[Refueler]

Or you could pull the transducers.

Ok - sitting in airport lounge ...

Not viable - two are fixed unknown type ... I mean REALLY fixed !!
Other three - no idea when last pulled - if ever ... so do not wish to risk them being seized / cracking etc. I've seen them cracked when a little more force applied ...

Once she's lifted - then all will be revealed !!

 

[Refueler]

Depends on the boat and crane. In this case they couldn’t get the straps close enough for comfort so tied the strops together. I normally insist on it. View attachment 162978

That's a different ball game with deep long keel like that ...

 

[AntarcticPilot]

A point no one seems to have considered is that if you mark "lifting points" and the yard uses them and something goes wrong, they can blame your marks and shift liability. Of course, @Refueler is both experienced and skilled as a surveyor, so in his case, there isn't much risk. But for most of us, if I were putting marks on, I'd mark points to avoid (saildrives, P-brackets, transducers etc.) rather than marking points to use. Then if there's a problem, it's the yard's problem! Of course, if marks are placed by the yard (and it seems to be fairly common practice) then that's their affair too.

 

[penfold]

A point no one seems to have considered is that if you mark "lifting points" and the yard uses them and something goes wrong, they can blame your marks and shift liability. Of course, @Refueler is both experienced and skilled as a surveyor, so in his case, there isn't much risk. But for most of us, if I were putting marks on, I'd mark points to avoid (saildrives, P-brackets, transducers etc.) rather than marking points to use. Then if there's a problem, it's the yard's problem! Of course, if marks are placed by the yard (and it seems to be fairly common practice) then that's their affair too.

Adopting some big ship practice and having an accurate scale drawing of the underwater profile with locations of transducers to show hoist/crane operators would be no bad thing.

 

[AntarcticPilot]

Adopting some big ship practice and having an accurate scale drawing of the underwater profile with locations of transducers to show hoist/crane operators would be no bad thing.

The overall point is that telling people what to avoid is a better strategy than telling them what to do.

 

[ribdriver]

And to add to the fun and games, quite a few manufacturers fit sling marks from the factory which are in the wrong place (ie likely to damage something). Especially on motor boats.

Line between the fore and aft sling = gut line. Always used to be a 'must fit' for long keeled yachts and plenty of others.

 

[Refueler]

A point no one seems to have considered is that if you mark "lifting points" and the yard uses them and something goes wrong, they can blame your marks and shift liability. Of course, @Refueler is both experienced and skilled as a surveyor, so in his case, there isn't much risk. But for most of us, if I were putting marks on, I'd mark points to avoid (saildrives, P-brackets, transducers etc.) rather than marking points to use. Then if there's a problem, it's the yard's problem! Of course, if marks are placed by the yard (and it seems to be fairly common practice) then that's their affair too.

I regard it as similar to TUG marks on ships ..... free to not follow - but damage can then be claimed against Tug !

 

[Refueler]

Sails now home ... boat readied for lift on monday ...

Its going to be interesting to see under her .... and to sort out the 6 transducers I have ... which are actually needed !!!

Then when weather is good and no strong winds - get a cherry picker chair lift (I need ~19m lift) to get at masthead .... to look at the B&G Wind gear ... swap filament bulb to LED in the anchor / Tri light up there ... then install flag halyards to spreaders .... LED bulb to steaming light ...