Every fan of gunkholing wants to know as much as possible about the depth of the water under their boat. And although Buzzards Bay is generally deep, there are a few spots where you really want to see what lurks below just to be on the safe side.

When I ran twin outboards, it was pretty easy. I’d simply trim them up until the skegs were above the low water point and have someone watch over the bow for trouble.

Once I went to single screw inboards, life got more complicated. I have eliminated West Falmouth harbor from my gunkhole rotation because the entrance hugging the beach is just too scary.

I haven’t entered Lake Tashmoo yet, but my friend Joyce tells me she sees plenty of big boats in there all the time.

I generally use a combination of the down looking depth sounder and reported depths on the chartplotter to pick a safe path through shallow waters.

One of my favorite gunkholes in Gooseberry Island near Newport. The first time I entered this rather treacherous little harbor I was quite nervous. It’s one of those coves with really tall rocks jutting out on either side.

What makes it even more scary is that the coastline doesn’t really align with whats under the sea. You have to hug the rocks to steer clear of the shoals and the kelp. But once you anchor, it’s a great spot.

My new Garmin has a view that I really like when I’m going through tight passages like the entrance to Gooseberry Gunkhole it’s called the 3D Fish View on the Garmin. It gives me a 3D view of the bottom contour calibrated to the actual depth feed coming from the sounder.

Vigilant has two 12″ screens, so I bring this view up on one and the standard GPS view on the other. I feel like I’m steering a battleship through a tight channel and it really gives me confidence to proceed.

Garmin PANOPTIX – Forward Looking Sonar

Scott at SK told me about Garmin’s forward looking sonar when we were outfitting Tenacity. It was still on the drawing board in 2015, but when it came time to build out Vigilant, we put it on the electronics list.

It was originally created for small fishing boats where the transducer would protrude out from below the hull and provide enhanced views (more on this later).

The big boat version still quite valuable for shallow and tight spaces. The most common application is pulling into a tight slip like Ballard’s on Block Island.

I also rely heavily on it when I’m assigned one of the near beach spots at The Black Dog Wharf…

A third is the inner slips at Brewster’s in Plymouth, where the GPS charts report no depth whatsoever!

In all of these cases, your eyes are not your friend!

In the case of Block Island, everything looks fine, but I knew from reports there was a field of rocks between the marina and the beach. In the case of both The Black Dog and Plymouth, it looked like I has no water at all and I was surely going to run aground.

The Fore Vu PANOPTIX gives me a two dimensional cross section of the water in front of me and the depth. Sometimes it looks out 200′ and some time it’s just 60′.

Here are a couple of views:

This shot entering Red Brook harbor form the south behind Bassetts Island, a narrow channel lined with rocks. This shows me that I have a minimum of 8.7 feet of water 120 feet out…
This from the inner slip at Mattapoisett Boat Yard facing the beach. Here I have 2.1′ under the boat going to 0 about 50 feet out.

RealVü 3D Forward

For those of you in smaller craft, Garmin offers some super cool gear for looking around under the water. They call is RealVü 3D Forward and it looks like this:

I’m thinking this is one of those little electric motors you see on Bass Boats and this version is all about fish finding.

Here’s how they describe it:

Scans the area in front of your boat, creating a forward-looking 3D view of the bottom, structure and fish. You can control how quickly the forward area is scanned to provide greater or less detail, making it very easy to identify where the fish really are.

Nice words, but you really need to see some of the realtime graphics to fully appreciate this powerful tool.

Here are a gif of the kind of views you can get..

Toy or Real Tool?

I’ll defer assessing the value of the 3D version to fishermen. In terms of the big boat version, I have to say that it’s one of those things that cost a fair amount of money ($1,500 plus installation),  seldom used, but when you need it, it’s priceless!

Yes, the The Garmin PANOPTIX is a real and valuable tool.