Stabilizers for Blue Angel, engineering question

[BartW]

Maybe you could use ultrasound to measure the hull, non destructive and you could measure anywhere you like.

pls explain how this could be done easyly,
I don't have any tools to do this (despite my sound business ;-) )

 

[Erik C]

It is most often used for surveys of steel yachts but works on frp boats as well, it should not be to difficult to find a surveyor or yard that has the necessary equipment.

an example.

http://www.olympus-ims.com/en/applications/thickness-gaging-fiberglass-boat-hulls/

 

[MrB]

I am sure a boat yard would have a meter. Maybe something like this? http://www.sonatest.com/products/range/thickness-gauge/t-gage21/

 

[BartW]

It is most often used for surveys of steel yachts but works on frp boats as well, it should not be to difficult to find a surveyor or yard that has the necessary equipment.

an example.

http://www.olympus-ims.com/en/applications/thickness-gaging-fiberglass-boat-hulls/

interesting sugestion,
this is even affordable for buying, perhaps silly for one -off usage
http://www.dmv-uk.com/dmv350-ultrasonic-thickness-gauge/p290

 

[jfm]

interesting sugestion,
this is even affordable for buying, perhaps silly for one -off usage
http://www.dmv-uk.com/dmv350-ultrasonic-thickness-gauge/p290

Yup, i hadn't realised those ultrasound meters were so cheap these days. So your choice is
1. bent knitting needle, wet bilge, €zero
2. Ultrasonic meter, dry bilge, £179, and a nice tool to add to your toolkit and never use again

 

[newWave]

Just my 2c, before opening the seacock dive in and plug a cork in it (afterwards measure how deep you plugged it in), then measure from inside as jfm suggested.
This will save you a bilge cleanup, but you will have to get wet twice.

 

[BartW]

Just my 2c, before opening the seacock dive in and plug a cork in it (afterwards measure how deep you plugged it in), then measure from inside as jfm suggested.
This will save you a bilge cleanup, but you will have to get wet twice.

or a variation on the theme,
put a brass plug on top inside,
and measure from outside


this forum is brilliant

I'm nevertheless considering ordering the ultrasonic meter, to do different measurements at different positions,
but one accurate measurement with the knitting needle, (and scratch off many layers old antifoul first ....)

 

[BartW]

Just my 2c, before opening the seacock dive in and plug a cork in it (afterwards measure how deep you plugged it in), then measure from inside as jfm suggested.
This will save you a bilge cleanup, but you will have to get wet twice.

This makes me think about a old riddle that you all know I think (its boaty !)
There is a peasant on the river bank with a big dog, a lamb and a basket of cabbage
He has to bring the 3 items to the other side,
But the small boat only allows for one item at a time,
How to do this, but preventing that The dog can eat the lamb Or The lamb can eat the cabbage.

I’m only interested to hear your answer if you don’t know the riddle

 

[rwoofer]

Another variation for you, stolen from a raggie hole fixing solution, which is to strap a sail under the hull to stop the water ingress....

Drag any impervious material under the boat (such such as small tarpaulin), strap it down, remove seacock hose, push needle down till you hit tarpaulin. That way you don't even need to get wet.

 

[newWave]

I suggested plugging the outside as covering the inside might be a problem due to the construction of the seacock.
And yes I know the answer to the riddle, so won't spoil it for the others.

 

[jfm]

This makes me think about a old riddle that you all know I think (its boaty !)
There is a peasant on the river bank with a big dog, a lamb and a basket of cabbage
He has to bring the 3 items to the other side,
But the small boat only allows for one item at a time,
How to do this, but preventing that The dog can eat the lamb Or The lamb can eat the cabbage.

I’m only interested to hear your answer if you don’t know the riddle

You take the lamb first then sail back empty.
Next take dog but bring the lamb back on return journey
Next, take the cabbage, and sail back empty
Finally take the lamb

However, on this forum we would wrap the dog in a sail and stick a bent knitting needle in the lamb, and take all three together not caring about the CE plate on the boat that says maximum passenger or horsepower, because we know better.

I love it BartW that you propsoal is to do the knitting needle and diving, and buy the ultrasound device AS WELL. You are a proper addicted crazy boater Love it!

 

[jfm]

That way you don't even need to get wet.

Yeah but he WANTS to get wet rb_stretch

 

[rafiki_]

This makes me think about a old riddle that you all know I think (its boaty !)
There is a peasant on the river bank with a big dog, a lamb and a basket of cabbage
He has to bring the 3 items to the other side,
But the small boat only allows for one item at a time,
How to do this, but preventing that The dog can eat the lamb Or The lamb can eat the cabbage.

I’m only interested to hear your answer if you don’t know the riddle

I'd take the lamb and the cabbage in 1 trip, and let the dog swim.

 

[BartW]

but he WANTS to get wet

I'm not that much seduced to jump in the water in a port,

Drag any impervious material under the boat (such such as small tarpaulin), strap it down, remove seacock hose, push needle down till you hit tarpaulin. That way you don't even need to get wet.

but I do need to measure the thinckness of the flange of the seacock under water

that you propsoal is to do the knitting needle and diving, and buy the ultrasound device AS WELL.

The ultrasound device is ordered online,
and my mum has a knitting needle available for me,
so all is under controll now

 

[MapisM]

I love it BartW that you propsoal is to do the knitting needle and diving, and buy the ultrasound device AS WELL. You are a proper addicted crazy boater Love it!

LOL, how very true... And you've not yet heard of converting every alu parts to brand new shining chromed ones...!

Anyway, now that the measurement method is sorted, shall we make this thread really interesting with some bets?
My guess is a couple of inches.

 

[Piers]

Stab Position

Hi Bart,

Apologies if this has been covered, but I was once part of an interesting discussion concerning the positioning of stabs which included the fact that an incorrect position would casue the autopilot to fight stab corrections since stab movement would alter boat heading. Depending upon the sea state, it could become a nasty form of what I'd call Dutch Roll (flying term), or corkscrewing. Getting an architect to nail his colours on the correct position wojuld be something I'd do.

Again, apologies if this has already been mentioned.

Piers

 

[BartW]

And you've not yet heard of converting every alu parts to brand new shining chromed ones.

don't reveal that one yet MapiM, because that appears to be a much bigger tasc then fitting stabs to a boat
we might need a separate thread for this

Anyway, now that the measurement method is sorted, shall we make this thread really interesting with some bets?
My guess is a couple of inches.

Had the same question in mind, but 2inches is too positive I would say
but absolutely no idea myself, 35mm perhaps

 

[BartW]

an interesting discussion concerning the positioning of stabs which included the fact that an incorrect position would casue the autopilot to fight stab corrections since stab movement would alter boat heading. Depending upon the sea state, it could become a nasty form of what I'd call Dutch Roll (flying term), or corkscrewing. Getting an architect to nail his colours on the correct position wojuld be something I'd do.

fighting stab controll soft and autopilot, this topic has been well covered or discussed by Jfm and MapisM in another thread some months back,
and iirc there was no formal agreement on that.

The exact position of the stabs would be determined by the supplier CMC, they have the engineers and knowledge for that,
but they might need some parameters from the boat that we don't have, and that a Naval architect could maybe calculate,

but your remark is valid !

 

[jfm]

My guess is a couple of inches.

Put me in for "just" 30mm

 

[MrB]

47mm for me.