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Old 09-05-2022, 01:09   #1
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What are these disks on the hull?

Hi all,

I've been stripping the interior of the new boat. As I have progressed I have found a number of these disks on the inside of the hull, below the floor.

The boat is solid fibreglass, laid up in 1978 by Yu Ching Marine in Taiwan.

None of the disks appear to align with anything inside or outside the boat.

So far I've found at least half a dozen.

Matt
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Old 09-05-2022, 01:34   #2
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Re: What are these disks on the hull?

Quote:
Originally Posted by GILow View Post
Hi all,

I've been stripping the interior of the new boat. As I have progressed I have found a number of these disks on the inside of the hull, below the floor.

The boat is solid fibreglass, laid up in 1978 by Yu Ching Marine in Taiwan.

None of the disks appear to align with anything inside or outside the boat.

So far I've found at least half a dozen.

Matt
Attachment 257431Attachment 257432

Maybe Lightning Protection?


"Kelly Peterson 44' 1976 “ISOLA”
YC4411803760 – Hull 18
Tawain - Yu Ching Boatyard
$99,500
Isola has been through several major updates since her purchase in 2007, and id ready to go
Sailing. All Thruhulls and hoses replaced. All electrcial Replaced per ABYC standards. All
chainplates replaced. New Aluminium Diesel fuel tank. Refrigeration box replaced. Propane
system replaced. Added lightning protection system. New Main Sail Stackpack. New Bimini
Full Cockpit Enclosure. 9ft Achilles Dingy with 4HP motor included. Too many upgrades to list.
The boat is located in Great Kills Harbor in Staten Island NY 10308.
Engine:
British Leyland Diesel Engine
Y-154 - 60 hp
Batteries:
4 Trojan 6 Volt Wet Cell Batteries - 335 Amps Trojan J305H
Sealed AGM Start




https://kp44.org/forsale/isola/Isola_Brochure.pdf



https://www.cruisersforum.com/forums...it-243119.html
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Old 09-05-2022, 03:48   #3
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Re: What are these disks on the hull?

Quote:
Originally Posted by GILow View Post
... None of the disks appear to align with anything inside or outside the boat ...
Quote:
Originally Posted by coopec43 View Post
Maybe Lightning Protection? ...
Good idea, but, I didn’t see anything on the hull’s exterior, which would be in contact /w seawater [lightning ground].
https://i.postimg.cc/zfdGjPzz/PXL-20...-140113908.jpg


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Old 09-05-2022, 04:00   #4
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Re: What are these disks on the hull?

On my HR we had a single similar disk which was part of the HF grounding. It had been disconnected and instead the HF had been connected to a large number of metal sheeting layed along the hull anywhere where there was spare space. Perhaps installed for HF grounding that was never used?

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PS: now at the Gold Coast Seaway, about to head further north.
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Old 09-05-2022, 04:15   #5
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Re: What are these disks on the hull?

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PS: now at the Gold Coast Seaway, about to head further north.

That’s right… rub it in.
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Old 09-05-2022, 06:19   #6
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Re: What are these disks on the hull?

What are the disks made of?

Is this a high volume production boat?

Might be a locator for a building jig or something to help getting the hull out of the mold...
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Old 09-05-2022, 06:49   #7
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Re: What are these disks on the hull?

+1 for SSB counterpoise mounting system......
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Old 09-05-2022, 07:37   #8
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Re: What are these disks on the hull?

Going out on a limb here, but back in that time frame there was a company, (forgotten the name,) that produced/advertised a system whereby "sonic pulses" were created by a remotely mounted oscillator and transmitted/carried by wires to "discs" located around the hull.
The premise was as a way to prevent barnacles from attaching themselves.
It used a frequency range that was above the human hearing threshold, kinda like a "dog whistle".
Purported to be a "Breakthru" in anti-fouling technology, it was short lived.
I guess the barnacles were supposed to be driven insane.
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Old 09-05-2022, 07:57   #9
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Re: What are these disks on the hull?

Gold Coast as in Surfers Paradise Australia!? NIce. Love it there.
Here is a wild guess they are fengshui coins to bless and protect the boat.

And can I say what a lovely hull
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Old 09-05-2022, 14:59   #10
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Re: What are these disks on the hull?

Quote:
Originally Posted by Franziska View Post
What are the disks made of?

Is this a high volume production boat?

Might be a locator for a building jig or something to help getting the hull out of the mold...


This seems the most likely explanation.
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Old 09-05-2022, 15:00   #11
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Re: What are these disks on the hull?

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Gold Coast as in Surfers Paradise Australia!? NIce. Love it there.
Here is a wild guess they are fengshui coins to bless and protect the boat.

And can I say what a lovely hull


Good theory, and a good reason to leave them alone.

The boat in the photo from GordMay is someone else’s boat, mine doesn’t look that good, but it is approximately the same shape.
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Old 09-05-2022, 15:03   #12
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What are these disks on the hull?

The HF grounding idea is interesting but the disks seem to be synthetic, there are no wires anywhere near them and their placement feels a little random for any kind of barnacle system.

I’m thinking it has something to do with the hull layup process, the idea of being part of a jig system makes good sense.
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Old 09-05-2022, 15:11   #13
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Re: What are these disks on the hull?

I will go out on a limb and suggest that a PO tried an ultrasonic antifoul system, found it as useful as just about everyone else that has tried one and removed all but the transducers glued to the hull.
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Old 09-05-2022, 16:40   #14
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Re: What are these disks on the hull?

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Originally Posted by GILow View Post
Good theory, and a good reason to leave them alone.

The boat in the photo from GordMay is someone else’s boat, mine doesn’t look that good, but it is approximately the same shape.

Since the hull was laid up in Taiwan and shipped to the US for fitting out were the discs part of a transportation jig? (maybe drawing a long bow)

"Approximately the same shape" This article may explain that?

https://bluewaterboats.org/kelly-peterson-44
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Old 10-05-2022, 02:17   #15
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Re: What are these disks on the hull?

Quote:
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... The boat in the photo from GordMay is someone else’s boat, mine doesn’t look that good, but it is approximately the same shape.
The boat in the photo I posted, is the Kelly Peterson 44, Coopec referred to.
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