Garmin 90 Fishfinder

[lakelandterrier]

I'm sure this a is a really stupid question, but ......

I've acquired a Garmin 90 Fsihfinder to fit to my 4M Avon.

I'm puzzling over how to neatly connect the power / transducer plug through the console. The plug is c. 30mm in diameter, although the cables are much less thick.

Do I need to drill a 30mm hole to pass the plug through - which seems the answer, but then how do I neatly fill the big hole into the consoile around the cables? With a grommit?

OR can I cut the cable, drill a small hole and reconnect the wires inside the console, but would this invalidate the warranty?

Not having fitted any electronics to a craft before I want to get it right & not make a pig's ear of the job.

All advice gratefully received

LT

[Searider]

Have a look on the Index Marine website. They have some glands with a rubber insert that will be just the job.

[jyasaki]

Cutting the cable will most likely not invalidate the warranty. Most warranty problems are with the head unit, which would, should something happen, be returned by itself.

jky

[mdt]

Cutting the wire will put interference into the signal too... well the resulting join will. I know it is a pain but just cut the 30mm hole.

[al40]

I've just had to cut the transducer cable on my FF90 so will let you know how I get on with joining it (installed original FF80 on boat but since then have installed a lot more cables through underfloor trunking so no way the cable connector would get through the trunk!) - FF80 broke so had to get new unit and transducers are not compatible :-(

The cable is double shielded (2 sets of foil shield with 2 signal wires in each shield). Also a twisted ground wire. I reccon it should be possible to re-join it all without any lack of signal integrity (solder each wire, re-instate shield and then shrink wrap it all).

[al40]

Quick update, last friday I re-joined the FF90 cable and it works fine.

Steps taken:
- Cut off a fair amount of inulation on each end
- CAREFULLY fold back the shield foil (4 cables shielded in sets of 2)
- Cut the signal cables a bit shorted then stripped off the insulation
- Fitted some small heat shrink tubing then twisted cables together so they were inline (ie join in midlle, cable to left and right)
- Soldered each connection then moved heatshrink to totally cover the solder joint and gently warmed with heat gun
- I then wrapped each connection in self amalgamting tape just to ensure there were no shorts as the heat shrink sleeve is fairly thin.
- Next (this was hardest part), re-instated the foil sheild.. I carefully re-wrapped the shields round the cables and then put a tiny blob of solder just to join them (carefull that don't melt the insulation of the wires underneath. Repeated for other shield
- Next, soldered the earth wire together
- Finally wrapped the whole thing in self amalgamating table to keep it from moving and also make a waterproof cover.

Cutting the cable was a last resort and not something I really wanted to do but it doesn't seem to have impacted the operation in any way....

[lakelandterrier]

Thanks guys for the advice.

I didn't however even get to the point of starting to mount the thing - the size of the mounting bracket makes to big to fit anywhere on the console.

This is a signifacant problem! I don't think - or can't find a unit any smaller, but do want to able to know how much water I have underneath (for anchoring etc...). Being able to find some fish on accasion would be nice too!

The solution I'm having to consider now is to fit a permanent depth gauge (c.2.5 - 3") into the console and get on of those battery operated fish finders that kayakers etc use for the fish finding.

Is there a smaller, reliable, but inexpensive fish finder suitable fro a small console, or are there any other options?

By the way, the very nice people at Ash Marine in Topsham took the Garmni unit back with a full refund - excellent

LT

[jyasaki]

Originally Posted by mdt

Cutting the wire will put interference into the signal too... well the resulting join will. I know it is a pain but just cut the 30mm hole.

On a fishfinder? Not real likely (but, possible, I suppose.) The shielding is there to keep the signal in, not to keep other stuff out (prevents VHF interference, etc.)

jky

[al40]

Originally Posted by jyasaki

On a fishfinder? Not real likely (but, possible, I suppose.) The shielding is there to keep the signal in, not to keep other stuff out (prevents VHF interference, etc.)

jky

My guess would be it's a bit of both. There will be fairly high energy pulses to power the transducer as well as low level signal being returned for depth info. The likelyhood of the depth signal being susceptable to external interference is high whereas the likelyhood of the pulse causing interference is also high.

I recall a bad earth on a seafarer echosounder (proper spinny analogue unit) that meant the radio (tranny) picked up the noise from the pulses! Also seen an echo sounder pick up interference from adjacent electronics (think it was the Log - can't recall) again due to bad earth.

[IBWET]

Originally Posted by al40

My guess would be it's a bit of both. There will be fairly high energy pulses to power the transducer as well as low level signal being returned for depth info. The likelyhood of the depth signal being susceptable to external interference is high whereas the likelyhood of the pulse causing interference is also high.

I recall a bad earth on a seafarer echosounder (proper spinny analogue unit) that meant the radio (tranny) picked up the noise from the pulses! Also seen an echo sounder pick up interference from adjacent electronics (think it was the Log - can't recall) again due to bad earth.

Well,did you get a bag of chips?..

[al40]

Originally Posted by IBWET

Well,did you get a bag of chips?..

Nothing but Rothesay's finest - and a fairly lumpy ride back

[DonMacN]

probably irrelevant now that the OP has gone for another option but....

I have a Garmin 90 and when fitting it I realised i had to cut the 30mm hole. Really didn't want to cut the cable, and my solution seemed less hassle in the long run.

What I did though was to mark the ideal cable location, then drill a hole the right size for the cables. ie something about 6/8mm. Then I cut out the 30mm hole with a hole saw making sure that the outer diameter of the hole just overlapped with my original 'cable hole'. (sorry - this sounds complicated already!)

KEEP THE CUT-OUT! I then put the cable plug through the 30mm hole and popped the 30mm cut out back in place with some 'marine sealant' and also sealed around the cable and the centre hole left by the hole saw. It's not the prettiest solution, but at least it keeps the water out of the console.

I've just used this approach again when fitting the new control box. All the connectors for the loom needed a much bigger hole to fit through than the cables themselves and I really didn't want dollops of water getting in there to the battery/loom etc etc.