Forward looking depth finder

Chuckpacific · Posted: Mon Feb 19, 2007 11:21 am Post subject: Forward looking depth finder

Saturday I was at Sportcraft and heard about a forward looking depth finder. According to them it has two transponders which fit on the back/bottom of the hull at the rear. The transponders are hinged and can open(?) to allow for collisions with debris coming under the hull. The unit gives depths 50 ft ahead of the hull. Does anyone know anything about this unit. According to Sportcraft they had installed one of these on a red CD-16.
Also, does anyone have a thru-hull (inside the hull) transponder and if so, how does it work?

Chuck

rogerbum · Posted: Mon Feb 19, 2007 1:28 pm Post subject:

I have a forward looking sonar - the Interphase Sea Scout. I have to admit that I'm not too happy with it. I was about $1,000 when I bought it. I had the idea that it would be useful for fishing - e.g. I hoped I could use it to find a bait ball and steer to it. In practice, the resolution is so-so, it loses bottom quite easily and throws static on my radio. In principal, it could be useful for shallow approaches and I have used it that way. However, where I boat, the mapping detail is pretty good on the GPS and I generally go so slow when I'm in doubt about depth, that the foward looking depth finder has not been that useful. Hence, I use it in conventional downward looking mode 95+% of the time and the performance in that mode is so-so. I wish I had bought a Lowrance, Hummingbird matrix or Furuno instead.

thataway · Posted: Mon Feb 19, 2007 3:05 pm Post subject:

I don't own forward looking sonar, but have run boats which have it. You can only see about 6x depth ahead. So if you are in 10 feet--you "see" 60 feet ahead. This does not give enough margin of error. They don't work well in sloping sandy bottoms, do not give a definate "edge".

They are fairly good at very slow speeds, where there is deep water and then a rock or ledge. But again, best at slow speed.

Better is a true forward scanning sonar--such as made by Westmar or furuno--but this may cost more than the boat!.

Echo Pilot and Impluse are the two major phased array builders of this product for small craft--I don't see where a hinged product would be any better.

drjohn71a · Posted: Mon Feb 19, 2007 3:29 pm Post subject:

Steve, I had the old Interphase "Probe" installed on my old houseboat. The Scout looks ahead at a wide angle, but shallow and the Probe looks ahead in a narrow beam going from ahead to straight below.

The new units are a combination and have more options.

I initially got mine to help find overboard accident victims, but it came in handy for negotiating the many shallow areas in our local lakes.
My experience is that, in shallow water, it only gave about 3-4 times the depth advanced notice of a shoal. The shallower the water, the less advanced notice you get. Still, going very slowly, one could negotiate extreme shallows.

I am in love with the idea of the Twin Scope, etc., but the reality is not as elegant.

John

Gene Morris · Posted: Mon Feb 19, 2007 6:37 pm Post subject:

I have never had a Hummingbird product. I have never heard anything good about them. However, Hummingbird just came out with a new sonar that is forward and downward looking. The computer then translates the data into a 3d (nearly photo like) image of the bottom forward and downward.

I don't have any idea weather it is any good but, the advertisements look great.

Gene

thataway · Posted: Mon Feb 19, 2007 7:09 pm Post subject:

Gene, I think you are refering to the Hummingbird Matrix. 47 3D or 947 (and some others which include GPS). The 47 3D Has 11 phased array transducers, so that you get a cross section of the ocean floor at a beam width of 53 degrees. I believe it only shoots below the boat--and is not foreward looking, as the Interphase or Echo Pilot (or true scanning sonar).

However, despite the great looks in the catalogues, there have not been any great reports on the various fishing forums which I have seen. It really looks great on the web pages, but if it was as "hot" as described in finding structure I am sure that the sportfisherman would have latched onto it and given it good reviews.

When we have a question we send the dinghy ahead with me and a depth finder in the dinghy and Marie drives the boat following me, communication via walkie talkie. I wish there was a really good in-expensive side scan or foreward scan sonar!

Almas Only · Posted: Tue Feb 20, 2007 5:58 am Post subject:

For images from the Humminbird 947c, go to the following:

http://www.c-brats.com/modules.php?set_albumName=album297&op=modload&name=gallery&file=index&include=view_album.php

It takes a lot of practice to understand what you're seeing, and I'm only beginning. Note, this unit is designed to scan to the side, not ahead.

Alma's Only

drjohn71a · Posted: Tue Feb 20, 2007 9:51 am Post subject:

Gene,

I too was interested in the Hummingbird Side-Scan unit for awhile. Please note that the side scan function only works in less than 150 foot of water depth. While some of the ad pics show easily understood screen photos of underwater structure, most of the screens are pretty tough to figure out.

As aforementioned, it shoots to the side, not to the front. I was on a site discussing it and they were somewhat frustrated in it's inability to read clearly as you are passing shallow bank areas, looking for fish, even tho it's ads diagram this scenario.

John