Does anyone have any idea why I have these things on the hull of my boat?

[asteven221]

Recently my Sealine F44 was hoisted for it's bi-annual maintenance. It's only the second time it's been out in the time I have had the boat. Although I noticed the two strange items during the the last occassion, I didn't give them much thought and just assumed they were some sort of sensors/transducers or something like that.

This time I have had a closer look and I am stumped as to what they are for.

This is the first one - marked "Groundplate 04", which I assume is some sort of electrical earthing plate, although I have never seen one fitted on any previous boat that I have owned. Why would I have one fitted to my current boat?



The next thing is a complete mystery to me, which is attached to the bottom of the "keel".



If it was cleaned it looks like a zinc anode (it isn't) or a galvinised object. It's not clear on the photo but it's a diamond shape when viewed from underneath.

I have not investigated inside the boat yet, so apologies for not doing that before posting. There aren't any particularly unusual electronics on board. All standard Raymarine stuff from circa Y2000 era. There is a Vetus genny. The previous owner had satellite telly, which was removed prior to my ownership.

Thanks for any information given.

 

[jfm]

First one is electrical ground. The concept is normal, but afaik most builders just use a P bracket and don't fit an additional component. On the inside of the boat there will be studs with all the electrical 0v and earths connected

Second one is hard to diagnose from that pic and I'm not sure. Usually diamond things are blocks for transducers but there's no transducer here so I dont know

 

[oGaryo]

by the power of google and as per JFM's post:

Ground Plates are the necessary interface between electric and electronic board devices and the dissipator element: water.

 

[capsco]

I thought the second picture was of your landing gear.

 

[BartW]

the second looks like the transducer from a depth sonar / fish finder

 

[asteven221]

Thanks for the replies.

I think an investigation on the inside of the hull is required! I will check it out this weekend and report back for anyone interested - especially the "landing gear" thing - whatever it is!

 

[Robg71]

Second pic is a fish fryer (Sonar)
Or its a blank if sonar has been removed

 

[PaulGooch]

Second pic is a fish fryer (Sonar)
Or its a blank if sonar has been removed

I agree with Rob, 2nd pic is a flush mount sonar transducer. That's assuming we're looking at the object that's almost dead centre of the pic. Most certainly doesn't doesn't look diamond shape to me, looks round.

 

[John100156]

Do you have an Echopilot fitted? If so they may be its sensors, one each side of the boat?

 

[jfm]

Do you have an Echopilot fitted? If so they may be its sensors, one each side of the boat?

My echopilot (2008, "gold" model) only had one sensor and it didn't look like the thing on the keel of this boat

 

[Bilgediver]

Recently my Sealine F44 was hoisted for it's bi-annual maintenance. It's only the second time it's been out in the time I have had the boat. Although I noticed the two strange items during the the last occassion, I didn't give them much thought and just assumed they were some sort of sensors/transducers or something like that.

This time I have had a closer look and I am stumped as to what they are for.

This is the first one - marked "Groundplate 04", which I assume is some sort of electrical earthing plate, although I have never seen one fitted on any previous boat that I have owned. Why would I have one fitted to my current boat?

View attachment 27589

.

The groundplate (Dynaplate)

http://www.marinco.com/files/support/product/manuals/dynaplate.pdf


Maybe the boat had SSB radio or some other equipment needing a clean earth link other than DC negative.

 

[sarabande]

dunno if this helps...

 

[PaulGooch]

dunno if this helps...

I assumed that's what we were supposed to be looking at, which (IMO) is a sonar transducer.

 

[jimmy_the_builder]

I assumed that's what we were supposed to be looking at, which (IMO) is a sonar transducer.

I think you're right, if you were a gambling man you'd have a punt at an Airmar P319, no?

Cheers
Jimmy

 

[PaulGooch]

I think you're right, if you were a gambling man you'd have a punt at an Airmar P319, no?

Cheers
Jimmy

Indeed i would Jimmy, don't think i'd get very good odds though.

 

[Nick_H]

dunno if this helps...

I thought we were looking at the metal "fin" protruding from the bottom of the hull, which at first glance looks as though the van behind has got its side door open.

 

[asteven221]

Yes we are looking at the thing protruding out the bottom of the hull - not the heads inlet as per the photo attached by sarabande.

Incidentally it is definately not round and is indeed the shape of a diamond. It's about 14cm long, 9cm wide and about 2cm deep.

There isn't any evidence of any fancy new electronics, but there is an old flat screen crt "Raytheon" fishfinder with a navigator. There is also an old navtex that outputs on a roll of paper. The Raytheon gear looks as if it would have been good in it's day and appears to be mid 90's vintage. Maybe that's what the "thing" is for!

As for the ground plate, I would have thought that a P bracket would be better that a small 10cm plate.

Cheers.

 

[jimmy_the_builder]

Yes we are looking at the thing protruding out the bottom of the hull - not the heads inlet as per the photo attached by sarabande.

Got any better photos?

Cheers
Jimmy

 

[Nick_H]

Got any better photos?

Cheers
Jimmy

Yep, here's a better one ..

 

[jimmy_the_builder]

Yep, here's a better one ..

You're on fire these days, aren't you? Got a bit too much time on your hands perhaps?

Cheers
Jimmy