Frwd Looking Sonar - To Buy Or Not?

[GOBKJA]

We are considering purchasing an Interphase Forward Looking Sonar for our world cruise. One of us is hot on the idea, the other is lukewarm. We have a steel boat. Is it worth the investment? If anyone has any thoughts or experiences I would be grateful to hear them.

[MMNETSEA]

With a steel boat - need to cut new hole for transducer, and depending where the boat's keel is located may have to cut 2 holes (one either side of the keel) The transducers are linked electronically to give 180 degrees ahead of boat. The claims regarding distance efficiency are not borne out by reports.

The option for a transom mounted transducer does effect efficiency.

My understanding is that the forward looking efficiency is a function of depth. One needs a depth sounder in shallow water, therefore if the depth is say 20ft then the obstacle ahead may only show up when your boat arrives on top of it!

BTW, it is sold without a monitor (that's an option) you may be able connect it to a laptop or other navigation instrument.

I would certainly want a quality depth sounder on any boat = but not impressed by the hype for FLSs.

PS. For a steel boat, if the transducer is bronze then the thruhull should be Marelon (or similar)

[redbopeep]

We have one. It is worth it if you're going into poorly charted rocky areas or even anchorages cluttered with debris. Not so great for picking up on things like sand bars or other subtle changes in bottom depth.

Is it worth it? For us yes. If you are investing more than 200K in a vessel... sure. If you are on budget and looking at 50K...it wouldn't make the cut IMHO.

[GRANDSAILOR]

We have had one for the five years we have been cruising and love it. We are divers so it's great when pulling up to shallow reefs. It also doubles as a backup fathometer which has come in handy when the other one goes on the fritz.

[redbopeep]

Originally Posted by GRANDSAILOR

It also doubles as a backup fathometer which has come in handy when the other one goes on the fritz.

Yes, our DST sometimes freaks out so having the FLS is a good thing for back up. Further, the DST is near the back of the boat and the FLS is near the front, so they're actually looking at different areas (they're about 20 feet fore-and-aft away from each other).

[Aquaria]

Any experience of the FLS picking up floating (dangerous) debris like containers, big boxes etc? The chances to hit one on the high seas are slim but it haunts my mind ever since...

Uwe

SY Aquaria

[Nausikaa]

Uwe,

I have never used FLS but have quite a lot of experience in conventional SONAR. They look forward but also to both sides and astern but can not be titled sufficiently upwards to detect a container floating on or just below the surface. Perhaps FLS can but I doubt it.

Incidentally, some containers were lost not long ago from a ship off Gotland. Despite searches by the Swedish Coast Guard using the most modern air-bourne remote analysis systems, nothing was found and the search abandonned. It does make sleeping at sea in small vessels more difficult!

Aye // Stephen

[delatbabel]

I hit a telephone pole once. Not unusual in a motor vehicle but a bit unusual in a sailboat. It was a wooden pole floating about 30nm off shore. Fortunately I have a steel boat. It made an awful bang, and a reasonable dent on the port bow just below the waterline.

[redbopeep]

That's more unexpected so far away from land. Just last week, the USCG came up on the channel 16 with a notice to mariners to keep a lookout for a telephone pole that was drifting through the nearby channel. Fairly common here.

[Aquaria]

... and right now new floating debris in the coastal waters of Madeira after the severe storm of last weekend!

We were in Funchal/Madeira in 1993, when a storm of almost similar impact hit: Lots of debris coming down the barrancos at night.

The floating debris clogged the marina and rocks of all sizes the entrance. We had to wait until the entrance (right next to a barranco) was dug out again and used this time to clear the marina of the biggest items like refrigerators, tires, gasoline tanks and lots of wood, bringing me back to the topic: When leaving for the Canaries we still met some of the floating debris and especially during the first night felt rather unsafe.

With raising storm activities and men still building in unsafe areas it sure makes sence to have a FLS even when sailing in coastal areas.

Uwe

SY Aquaria