Depth gauge, raymarine E70207 - 2 questions

[landonshaw]

I am looking at buying the raymarine E70207 depth gauge. I am slowly migrating to raymarine products. The transducers are plastic or bronze. I have a fiberglass sailboat.

1.) Recommendations on one over the other? Does the bronze need special antifoulant? I have a plastic one now.

2.) They come In a 12 and 20 degree tilt. How do you measure to determine which one?

Comments on the depth gauge are also welcome.

Thanks.

[boatbod]

Plastic (nylon) transducers are generally fine for fiberglass boats. Bronze is a requirement for wood hulls.

Transducer element angle is a function of hull shape. How many degrees from horizontal is the hull at the mounting location? The xdr will tolerate some misalignment (beam width is typically 40deg) but a closer match is better and will result in less loss of signal underway.

[landonshaw]

Thank you, I understand the concept. While the boat is in the water, what is the easiest way to measure this angle?

Aloisius

[boatbod]

Originally Posted by landonshaw

Thank you, I understand the concept. While the boat is in the water, what is the easiest way to measure this angle?

Aloisius

You can't with any degree of accuracy.

Perhaps you can estimate by using an inclinometer (angle gauge) inside the hull, but I've seen far too many boats with different inside and outside measurements caused by stringers etc.

[landonshaw]

Thank you, I guess I will just swim under the boat and estimate how steep the incline is.

[boatbod]

Originally Posted by landonshaw

Thank you, I guess I will just swim under the boat and estimate how steep the incline is.

Well that's a possibility if you have a plastic inclinometer that doesn't mind getting wet.

Sailboat?
What kind of hull profile? (Full keel, modified fin, fin, canoe?)
Where are you mounting the txdr?

Typical cruising sail boats are 20deg or more, but it really depends on the hull and mounting position.

[landonshaw]

We have a sailboat with a fin keel. The mounting will be just in front of the keel. Very similar if not the exactly the same as this picture.


Aloisius

[boatbod]

Looks like 0 degree mount in front of keel in the "V". This is good for txdr performance, but beware you may need a long stem transducer because the hull will be considerably thicker here.

The only way to know for sure is to pull the old txdr and measure the stem.

[landonshaw]

Yes, I am also going to do this in the water. The last one I put in I did that. I did have a professional diver with me. We got a cup of water in the boat...

[boatbod]

Originally Posted by landonshaw

Yes, I am also going to do this in the water. The last one I put in I did that. I did have a professional diver with me. We got a cup of water in the boat...

Now you got me. How you going to get sealant to cure leak free underwater? Good luck.

[DotDun]

Originally Posted by boatbod

Now you got me. How you going to get sealant to cure leak free underwater? Good luck.

5200 cures underwater. As long as there are no large gaps that allow pressure to push it out, it works fine.

[boatbod]

Originally Posted by DotDun

5200 cures underwater. As long as there are no large gaps that allow pressure to push it out, it works fine.

It's true that 5200 does cure with moisture, but you've got to get the parts assembled first, and there will be considerably hydrostatic pressure trying to force a pathway into the boat.

Not saying it can't work, but I certainly wouldn't try it on either my boat or any of my customers.

Please report back when you get it finished. I'm interested to hear how it works out.

[DotDun]

Originally Posted by boatbod

It's true that 5200 does cure with moisture, but you've got to get the parts assembled first, and there will be considerably hydrostatic pressure trying to force a pathway into the boat.

Not saying it can't work, but I certainly wouldn't try it on either my boat or any of my customers.

Please report back when you get it finished. I'm interested to hear how it works out.

I've seen it done.

1) Drill pilot (1/4") hole at location of transducer from inside the boat, leave drill bit in hole sticking out under hull (real short).
2) Dive and put sink plunger on hull over drill bit sticking out of the hull
3) From inside, use hole saw and drill final/bigger hole being careful to not dislodge sink plunger (diver ready to assist if necessary).
4) Apply liberal amount of 5200 on flange of thru-hull
5) Dive, remove sink plunger and immediate put thru-hull in-place while person inside boat puts rubber gasket and nut on thru-hull.

2 cups of water in boat at most!

[barnakiel]

We have the plastic one. It is fine. Grp boat. We have had it for about 15 years now.

You can measure the angle with a smartphone or else with a water level and a triangle.

b.

[boatbod]

There's an implicit assumption here that the depth transducer element is removable from the housing. Most are not, which would mean you have to drag the wire underwater and feed it through the hole first.