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Author Topic:   Electronics - Dauntless 160
alanfujii posted 01-27-2004 12:04 AM ET (US)   Profile for alanfujii   Send Email to alanfujii  
Well, I finally went and bought the Dauntless 160. Iím glad to do it since I was starting to second guess myself about going larger. I wanted to stay with my original objective. That was to get a simple all-around trailer able boat that I could manage by myself. The larger boat that will have to mainly fit my wifeís desires will have to come later but I will always have this one.
Now that I have made the plunge I would like to get feedback on how to equip it. Since I feel this is a boat that Iíll keep forever (I know you probably heard this beforeÖ) I donít mind loading it up more than normal for a boat this size.
I was thinking the following:

Garmin 188C GPS/Sounder with a bronze transducer
Icom 502 DSC with a direct connection to the GPS
XM Receiver Ė Delphi (portable between car and boat)
Poly-Planar Marine Stereo(Only one that is marine ready so it doesnít require covered housing)
Baystar Hydraulic Steering
Lenco Troll-N-Tabs

Comments on any of the above and is there anything Iím missing?

How would you approach the battery setup to run all this?
Iím having Dave from Seaside Electronics do all of the installation. He did my other boat and for the most part it was done very professionally.

millerbr posted 01-27-2004 07:53 AM ET (US)     Profile for millerbr  Send Email to millerbr     
Your plans sound great. Here's my setup that I have been very happy with:

Navman 5500i GPS (color, built in antenna, fuel computer)
Garmin FishFinder 240 Blue
Standard Horizon Intrepid+ VHF radio with DSC (to GPS)
Shakespeare 5240-R 36" low profile VHF antenna

Marlin posted 01-27-2004 09:17 AM ET (US)     Profile for Marlin  Send Email to Marlin     
Your electronics plans sound good. I installed a Garmin FishFinder 80 (cheap, but good enough for my use), a mount for my handheld GPSMap 76S, and a Standard Horizon Quest VHF (with DSC linked to the GPS). I originally had the VHF mounted low like millerbr's, but I kept knocking my knees on it, and my Golden Retriever likes to squeeze herself in between the pilot's seat and the console, so I moved it up and flush-mounted it above the cupholders. The GPS and sonar are on top of the console to the right. I like the setup, but a larger GPS screen would be nice.

I mounted a 3' antenna on the port side of the console just in front of the grabrail, but if I had to do it again, I'd have mounted it a little higher with a ratchet on the rail like millerbr's, but probably on the front side of the rail instead of the back side.

There are a couple photo links in this thread:

Hydraulic steering? Seems like a lot of work and expense to not get very much. The installed Teleflex no-feedback steering works fine, and with the 115 trimmed up a little there's very little steering force. You may need to play with the steering trim tab a little to even things out.

I'm not familiar with the Troll-N-Tabs, but there's very little room for a trim tab on the starboard side because of how the boarding ladder folds down. Take a real close look at that before you make any holes!

By the way, if your boat came with the outboard mounted all the way down, consider raising it one hole. It made a dramatic improvement to my ability to trim the boat without porpoising. See and/or do a site search for "dauntless porpoising", there's been lots of discussion on the topic.

Enjoy your boat!


cmarques posted 01-27-2004 08:15 PM ET (US)     Profile for cmarques  Send Email to cmarques     
Congrats on the Dauntless!
Here's what I have:
Raymarine Ray53 vhf w/DSC connected to GPS
Eagle 320df Seacharter combo gps/fishfinder
Ritchie Angler compass
8' Shakespere 5101 Centennial antenna (was going to use a 3' but go offshore now and then)
AM/FM cassette from Boater's World (Prospect?) with a waterproof cover.
I currently use a single battery deep cycle/cranking with no problems but may go to dual batteries as next project.
If your GPS has an internal antenna less space will be used as everything is a tight fit on the console but can be done. Post some pictures when you get it all done.
I had looked at quite a few radios and the Icoms and others seemed great and had more features than what I have but the Ray53 measured a little smaller to fit my ideas and to a lesser degree matched the gps and then found the compass the same-easier to justify to the misses "What's wrong with what you already have?"
I don't know much about steering or tabs but agree with Marlin about the swim ladder taking lots of room. I added Doel-Fins to my Merc 90 2s and made an improvement in less porpoising.
The only other electronic I'd like to install is some sort of fuel meter/computer- the gas gauge I think is useless. I came back into Port Canaveral once cutting fishing way short in a tournament reading dead empty in port to find only 22 gallons of fuel used.


alanfujii posted 01-27-2004 08:19 PM ET (US)     Profile for alanfujii  Send Email to alanfujii     
My only reason for the Baystar Hydraulic Steering is a concern on whether I will have to constantly hold the boat on course. I have to admit I got used to steering a boat using the autopilot. My goal is to be able to set the wheel on a course and only need minor adjustments to stay on course. Now maybe I'm underestimating the steering situation of my new boat. In the evaluation period, I went to a place that had a 2000 Outrage 18 for rent and took it out to get a feel for how the Dauntless would be. I understand they are different boats with very different hulls but it was good to give me a general idea of size etc. The downside was to the condition of a "rental" boat and on this particular boat the steering was fairly sloppy. I had to continually adjust the heading on the boat. This is probably more due to the abuse these rentals get but did open my eyes to the difference I may have in steering my new boat vs. the old boat.
I guess I'll wait and actual see how it behaves before I spring for the hydraulic.
By the way, my intent is to be able to sit back on enjoy the ride while I look ahead for obstacles. I understand the safety aspect on not setting a course and then go about the boat doing other things. I didn't do that on my old boat and defintely will not do that on this one.
Marlin posted 01-27-2004 10:28 PM ET (US)     Profile for Marlin  Send Email to Marlin     
If you're looking for the steering to hold a reasonable course, the Teleflex no-feedback should do fine. The boat wanders at low speed, but no problems at all much above idle. The down-side of the Teleflex is that the wheel has some play in it before it turns far enough to disengage the clutch and actually turn the motor. I found it very annoying at first, but after a few outings I didn't notice it anymore.


alanfujii posted 02-07-2004 03:02 AM ET (US)     Profile for alanfujii  Send Email to alanfujii     
I was having a problem trying to fit all the antenna mounting for the various electronics I was planning. I found the answer on one of the other posts. With some help from Carson Perry I've decided to get a T-top. Carson was nice enough to call me from Hawaii and answer any question that I had. To top it off he took some additional pictures of how the T-top was mounted. I decided to go an easier route and have Shock Boats handle the T-top installation for me.
There will be an enclosed eletronic box where I intend to put the VHF and stereo. I will also have mounting for the antennas, rod holders, flood light for the stern and nav lights on top. It cetainly makes a cleaner layout and gives me more room below.
jimh posted 02-07-2004 12:38 PM ET (US)     Profile for jimh  Send Email to jimh     
I'd throw out the audio entertainment/radio stuff and get an Apple iPod and a good pair of headphones. The Dauntless is too small to dance in, so the set of loudspeakers is not the best way to go. Generally I do not listen to recorded sounds and music while I am on the boat, as I prefer to listen to the sounds going on around me, the engine, the wake, the birds, the splashing, etc, or to actually talk with the people I am with. If I am alone and need music, it will sound better on a pair of headphones.

Most of that electronic audio stuff does not age well in a boat and then you have a bunch of odd holes in the laminate where it all used to be. You can take the iPod with you all the time and have all those recorded sounds and music available anywhere, not just in the boat. If you get iTunes (free) you can manage thousands of recordings and transfer them between the iPod and your PC. You can listen in the car--get a little adapter and you can play it through your car radio. You can have your own radio station.

Now if you want to keep up the the news while out in the boat, get a little portable from Radio Shack for $12.95.

Reception of AM radio is problematic on a boat due to the ignition noise from the outboard. FM radio just has music on it these days, so just bring your own in the iPod.

I'd get a handheld GPS so I could take it with me in the car or in other boats or to my next boat. Get a good mount for it and power cord so you can pop it into the console on the boat. Get some good software for it so you can take it home and plug it into your computer and have fun with all the data interchange that is possible these days. Get a second mount and use it in your car. Why have a $1000 piece of electronics sitting on the boat and only use it maybe a couple of hours a week?

It would be cool to get a Bluetooth GPS handheld and a Bluetooth computer--maybe even a laptop--and the two of them can talk without being connected. But I don't know if anyone has pioneered that yet, or not.

For the price of some of these fancy GPS color display marine electronics gizmos you can get a nice laptop AND a GPS handheld AND some cool software.

If you just want to know how deep it is get a not-too-expensive Fishfinder. If you want to hunt fish get a top of the line color Furuno or other highly-rated fish finder. I use a modest LOWRANCE as a depth sounder, a knot-log, a second speedo, and a digital voltmeter. I look at the SONAR rasterized display just to see the depth contour trend. Most of the time I have the read out set to just show digital gauges of the various functions mentioned above. About once a month it marks a fish, but I am not a fisherman. If I were, I'd have something that finds fish. But for a couple hundred bucks I get four or five digital gauges in one and a depth sounder. What a deal!

The Fishfinder makes sense because when I am not on the boat I don't care how deep the water is, how far the boat has gone, how fast it is going, or what the battery voltage is.

On the other hand, a nice GPS receiver is very useful when I am not on the boat, and being able to easily take it home and connect it to my computer is a big big plus.

Another thing to consider is the theft potential. Most guys do not leave $2,000 GPS receivers on the boat when they're not around, so you end up connecting and disconnecting the thing a lot anyways. Get something easy to disconnect and take with you--a hand held--and something you can use while you've taken off the boat.


Perry posted 02-07-2004 02:18 PM ET (US)     Profile for Perry  Send Email to Perry     
Alan, I'm glad I could be of help. I'm sure you are going to enjoy your new boat.

Jim brings up some good points, especially the use of handheld GPS. I often fish on friends' boats and like to take my GPS with. True, it has a smaller screen but I like the versitility of the handheld. There is also little chance of it getting stolen when it is locked in my house.

E-mail me if you have any further questions.


JohnJ80 posted 02-07-2004 02:33 PM ET (US)     Profile for JohnJ80  Send Email to JohnJ80     
I'm with Jim on this one.

Electronics and boats are just sort of problematic. The marine environment, especially if you are around salt water is just always a problem.

I have a Dauntless 15 so let me give you my perspective.

I have a Humminbird FF, but the Garmin would be great. Make sure it isn't panel mounted, but one that you can remove from the boat when you are not using it. This helps to limit exposure to moisture. On top of that, if you mount it on the top of the console, you can spin the FF so you can see if from anywhere on the boat - that is important.

I would recommend a bow mount trolling motor. My recommendation is for the Minnkota Autopilot series with the wireless control. The control is fantastic and it really is a low drag configuration. WIth my 55lb thrust AP motor, I swear I could waterski behind the boat. With the wireless and the Autopilot you can set and forget it for course and do it from anywhere on the boat. That would be tough with rear mount motors and you don't have the AP capability.

The Dauntless is bow light - with a deep V to keep you dry and for seaworthy characteristics. It also does not do well in a cross breeze at slow speed. You spin around pretty fast if you are not under power. For that reason too, I would suggest a bow mount motor. Trolling from the rear would not be all that easy to control, IMHO, at slow speed. I don't think I would recommend it. I fish on pretty big river and I really, really like the bow mount.

Also, there is enough weight in the back of the Dauntless - which are prone to porpoising anyhow, so adding those two big trim motors on the back is not particularily a good idea. I think too that because the motor sits up on top of the tabs (if memory serves) it will be a problem with the ladder if you have one. Tabs are great and recommended (you may not need or want them, try the boat first without) and should be fine with your ladder without the trolling motors. I can give you more information on ladders if you want. For Tabs, I like your choice of Lenco simply because they use electrical wires instead of hydraulics and I think there is less stuff that has to go down the cable race and less mounting room is required overall (fairly dear on the Dauntless).

For radios, a waterproof one is good - I don't see much difference between the major brands. It is going to go out on you so I don't think I would get to involved in interconnecting them with other systems. My personal choice is for a handheld that mounts in one of those rubber VHF holders on the console. You could add an antenna and a speaker mike connection to the radio. Distance with your radio is going to be much more a function of the antenna quality and height that it is the power. For example, you would be amazed at the reach from an antenna on the mast of a sailboat set at a puny one watt of transmit power.

For batteries, I would strongly recommend two (or more) batteries. One to run your electronics off of (house battery and trollling motor) and the other for starting and motor. I also recommend a device that charges the batteries such as the Stealth one charging system ( that charges up your cranking battery first and then makes sure your alternator charges up your house battery. Fishing on the large river I'm on, the 10-15 minute run to the next spot usually charges the house battery up to 100% even after a fair bit of trollling. This is a great gadget. The only time I have ever had my battery on a charger is during winter haulout to trickle charge them. My motor puts out 35A on its alternator, but you should check and see what yours does. You can do the Amp Hour calculation and see how this works for you.

Setting your batteries up this way is important. You absolutely do not want to have your cranking capability compromised by your electronics usage. You need min 10 volts or so to start your batteries. Most electronics will run just fine with less than that - you will have no warning your battery voltage is too low until you try and start.

For stereos, I like Jim's idea of an iPod or portable. On all my years of boating, I have never seen a stereo that really held up well. Every boat has one, and they always seem to age a lot faster than other electronics. The CD drives don't handle the vibration and moisture (humidity) well and the electronics are heavily susceptible to corrosion since they usually aren't potted or conformally coated.

If you use the iPod you could probably mount speakers and an amp (low cost) and then connect it easily to the iPod when you bring it on the boat. This deserves some thought before you start mounting stuff though.

You will also want to be fairly careful about how you mount all of this. A Dauntless has a farily tight place to mount all of this in the console. All of the wiring that leaves really has to go down the cable race to the back. It all gets pretty tight pretty fast (been there, done that).

Hope this helps.


alanfujii posted 02-08-2004 05:39 PM ET (US)     Profile for alanfujii  Send Email to alanfujii     
JimH and JohnJ80

I appreciate your recommendations. They are backed by a very logical and prudent approaches based on your experiences. This is why I appreciated this forum.

But let's just say in my case I'm somewhat less practical. Let's approach this from a different point of view and say that we have what my wife refers to as a "toy" and a looser budget to spend on the "toy". With that being the case and you had the opportunity to equip this little boat with a gift budgt of 8-10K what would you get?

I like the GPS (toy) but there is a safety factor to it. I want to link the VHF to it so in the event I was out on the water and something happen to me the kids would be able to push the distress button. My wife is extremely risk adverse which is why I still don't have a larger boat (Her idea of a boat that can go safely to Catalina is 50 foot plus). The stereo is also for the kids since I really don't like them running around with earphones both for safety and I would like to monitor what they listen too.

My major use of the boat will probably be cruising and fishing the Newport harbor. I thought the Lenco Troll-N-Tabs would be a good solution since I could trim the boat which would be necessary if I ever could convince my wife to go outside the harbor which is probably slim and none. Also the trolling control in my mind would be fantastic. You would have two electric motors with 134lb thrust on the each corner of the stern. I should be able to put this boat wherever I wanted. As for the bow mounted version, I was told I would have eliminate the bow rails which again for safety is not possible. The downside is the swim ladder which I haven't figured out yet.

JohnJ80 posted 02-08-2004 10:35 PM ET (US)     Profile for JohnJ80  Send Email to JohnJ80     
There are those that have apparently figured out how to mount a bow mount trolling motor on a dauntless with bow rails. Since you have big tinker budget, then I would just modify the bow rail so that you can switch the rail out of the way when you put the motor up or down. There are tons of fittings that you can get for that tubular rail that would make this work great. Ask your marine dealer about that. I mean, the 55lb thrust makes my dauntless really scoot along for a trolling motor. Goes fine through current, wind etc... I just think you would have a hard time going slow enough to be useful for fishing with 134x2 lbs of thrust. I would really caution against that. I also don't think it will track that well either.

With those two monster trolling motors, you are going to need to carry some serious battery if you want to have any life at all. I would check that out and even see if you can stash all the required batteries in the console. You may not have enough room. For example, those two motors running would have to use maybe 70A max (or more, my 55AP uses 40A or so wide open) each wide open - and with a typical trolling battery at 105Ah, that won't last long at all with both running wide open (like maybe 20 minutes per battery). You could toast the battery in short order.

I would look at the weight of those motors too. They have to go 30lbs each or so, so you would have 60lbs out aft of the transom on a lever arm. That could cause you some handling trouble (porpoising etc...). Be careful with that, this is after all, a 16' boat.

For stereo, consider just mounting the power amp and speakers and having a plug in to a music source such as an iPod. Either that, or put a radio in and use one of the FM tuner gadgets to broadcast the MP3 player to the radio. I just did that on a 10 day sailing trip and it worked great. My luck with built in CD players has not been good.

With all those extra gadgets, you are going to need some serious battery capacity. Make sure you allow enough room in the console (it is pretty tight in there), have it wired cleanly. I would also recommend the stealth charger because of the need to keep all this charged.


fno posted 02-08-2004 10:38 PM ET (US)     Profile for fno  Send Email to fno     
Alan, those trolling tabs will do a number on your ability to get up on plane with that boat. I would forget about them if I were you. Besides, that boat is so nimble anyway, you don't need them. Spend the money on stuff to get your wife in and out on that boat. Roses, diamonds, liquor all work well at times.
cmarques posted 02-08-2004 11:01 PM ET (US)     Profile for cmarques  Send Email to cmarques     
The cable passage on my Dauntless was crammed and hard to pull wires through- when I switched fishfinders I ripped the original cables trying to pull them back out. I found that the port side of the fuel tank has a 'notch' front to back and I snaked a 1 1/2" piece of tubing from the console to the bilge and was able to run fishfinder cables with no problem and have plenty of room for future wiring. That may be an idea if you plan on running stern trolling motors to make a lot of room for cables and other wiring.


alanfujii posted 02-09-2004 12:34 AM ET (US)     Profile for alanfujii  Send Email to alanfujii     
You bring up a good point concerning power management. All I was thinking that if 55lbs of thrust was good then more is better. I forgot that more means more power to drive it. Well you put enough doubt for me to back off a little and be more patient in what I think I need.
I'll start off with the T-top, Garmin 188C or 178C, Icom 502 and a solid marine radio that has FM reception. I'll put the VHF and radio in the electronic box on top and top mount the Garmin. This will allow me to try the Ipod or possibly the XM radio using the FM trnsmitter connection. I'll use the boat and get used to it before I even think of tabs, trolling etc.
This doesn't seem to be a lot of electronics, do you think I need a separate battery to run them?
jimh posted 02-09-2004 02:37 PM ET (US)     Profile for jimh  Send Email to jimh     
If you must have a GPS that mounts semi-permanently, look at the STANDARD 150. It is a WAAS Chartplotter that sells for less than $380 retail.

At the moment I do not think the U.S. Coast Guard is equipped to monitor DSC radios.

It would be a good question to clarify:

Can the U.S. Coast Guard radio watch receive distress calls transmitted with LAT/LON position information by DSC radios?

Moe posted 02-09-2004 02:55 PM ET (US)     Profile for Moe  Send Email to Moe     
Here's the info on the USCG upgrade, including an implementation schedule:

Although the USCG might not be able to receive it, an exponentially growing number of other boats will, and can relay that information to them.


JohnJ80 posted 02-09-2004 04:40 PM ET (US)     Profile for JohnJ80  Send Email to JohnJ80     
If you are going to fish, you will need a trolling motor. That isn't a major deal to set up.

I think the #1 reason people get stranded is due to battery issues. So, when it comes to boats, more is better (IMHO) especially if you can isolate them. Then if you have a problem, its a matter of moving cables (not fun, but doable in a pinch).

Each of those options probably draw an amp at least. The radio when broadcasting at max power, significantly more. So, the three of them probably pull an amp each average. If you have lights and are using them, that probably pulls another 3 amps or so. So, with all that going - its a 5A-10A load. If you are running slow, you may not be keeping up. I also don't know the charging specs on your motor, some have alternators that are as low as 12A (at 3/4 throttle or so) so you may be pushing the capacity on the whole system. The only way to fix that is to add more Ah, either in battery or alternator (different motor) if your motor has a small one.

Call me conservative or maybe its my big boat sailing experience, but I like having the accessories on a separate battery from the cranking batt. I used to worry all the time on my D15 with a single. I added the second battery for trolling and the alternator based charging system and moved all the accessories over there anyhow. Now I don't worry about it and it works great.

So, here is what I would do:

Check out Jim's concern about the DSC and the radio and answer that. the GPS, T top and radio are all good. (I fly fish out of my boat, so I don't care for T tops - they get in the way).

If you are going to fish, go for the trolling motor - bow mount - it is much handier for fishing (huge). Get your marine guy to fix the railing issue and make that work - should be straightforward. If fishing isn't a big deal, then wait.

Wait on the trim tabs until you see how it rides and you properly tune the motor to the boat (vertical height etc...). I personally love mine - and they greatly improved the ride (and hence spousal approval factor), but I wouldn't put those big motors on the back and I would wait until you have gotten some time on the boat so you know how she handles and rides and how to best use the power trim.

For ladders, I recommend (if it didn't come with your boat)

They work great with my trim tabs, it is an awsome ladder, and I like the smallish discrete platform. Just about the best ladder you can get.

I wouldn't worry about adding the ladder, the extra battery and charging system or the radio/FM/GPS. I would add an extra battery for all that and the charging thing (stealth charger), I would wait on the tabs for now (installing them is about a 2 hour DIY task for Lencos) should you be in a rush to add them. I would not add the big trolling motors integrated with the tabs under any condition.


alanfujii posted 02-09-2004 09:11 PM ET (US)     Profile for alanfujii  Send Email to alanfujii     
JimH, even though the Coast Guard is a bit behind in getting the receiving end of DSC technology up and running, I still see a benefit in having it. I understand that this does not replace my obligation to ensure my passenger's safety by teaching them how to use the VHF properly in the event of an accident which renders me incapacited.
John, I like your logic and will follow your path. The Mercury 115 outputs 25 amps according to their web site. This Stealth Charger sounds interesting. Do you have first hand experience with it? It sounds like the simplest and most effective way to wire your batteries and have them charged from one source. Actually it sounds to good to be true, any drawbacks?
triblet posted 02-09-2004 10:28 PM ET (US)     Profile for triblet  Send Email to triblet     
JohnJ80 is overestimating the current draw:

Bow light on my Montauk is 10W. .83 amps.
Anchor light is 15W. 1.25 amps.
My Standard Horizon Spectrum draws .5 amp if it's quiet, 1.5A
if someone else is talking, 6A if I'm talking. Usually it's
quiet, so say .6A average.
My Garmin 162 GPS pulls 4W. .33A.
My Humminbird Wide 3D Paramount pulls .25A.

That's 3.26A worst case (night, everything going).

A trolling motor does need it's own battery.


JohnJ80 posted 02-10-2004 08:41 PM ET (US)     Profile for JohnJ80  Send Email to JohnJ80     
Yep I probably am - I had forgotten what the running lights draw ( I always swag them out at an amp each). I definitely got a little high on the current estimate.

The real issue is what is the alternator current at low speed for the motor. If you are running all of that, and idling (say looking for a fishing spot or trolling) you can start to hit your battery pretty hard especially after a hard start or if you have EFI.

I don't know what the alternator is in that motor but I have seen some large motors that have puny altertnators - essentially just to refill the can after starting and not much more.

The other issue is the if you are not running the alternator fast enough (not enough RPM) to put out a decent charging current. If your battery is down because it wasn't run for a while or its cold or you left the lights on etc.... and then you putt around for a while, you might be going negative on the battery again. (that, incidentally comes from personal experience - happened to me with a worn battery and me spending a lot of time idling watching an on water event at night with some other accessories on). That won't happen with a dual battery set up since you will drain the house battery separately and still be able to crank your motor.

Batteries degrade over time. If you think that starting your boat is mission critical, or if you are going on big water, then putting in multiple batteries is important.

So, based on alanfujii's generous fun budget of $8K, heck, I'd build in the redundancy for sure especially for the ocean (even a harbor) because its easy to get to big water and redundancy=safety even more so on a small boat.


thesarras posted 02-29-2004 07:16 AM ET (US)     Profile for thesarras  Send Email to thesarras     
I just bought this winter a Eagle 320DF Chartplotter/Depthsounder for my Dauntless 15. It comes with both a skimmer transducer and a separate speed wheel.
Did you mount both to the transom?

I am a little leery to mount both...worried about interference with the bunk rail having the speed wheel adjacent to transducer. Transom is not very wide to begin with. Thinking about forgoing the speed wheel install.

If anyone has done both mountings on a D15/D16, I would sure love to see pix!


jimh posted 02-29-2004 10:26 AM ET (US)     Profile for jimh  Send Email to jimh     
The usual approach on a boat with a single engine is to mount the SONAR transducer on the Port side of the transom and the speed/temperature transducer on the Starboard side of the transom.
Moe posted 02-29-2004 12:33 PM ET (US)     Profile for Moe  Send Email to Moe     
I understand the logic of using the port side so that prop torque puts the transducer deeper in the water rather than lifting it higher. However...

Airmar makes many, if not most, of the transducers used by better fishfinder/sounders. This is from their FAQ (URL is too long to post) about mounting transom transducers:

Can transoms be mounted on either the starboard side or port side of the boat?

We recommend mounting a transom on the starboard side on single drive boats. The location should be a minimum of 3" from swing radius of the propeller.

Starboard mounting assures minimal aeration from the turbulance of the propellers, which can degrade performance.


jimh posted 02-29-2004 10:26 PM ET (US)     Profile for jimh  Send Email to jimh     
Because of the ten-inch setback bracket, the engine mount's setback, and the design of the lower unit, the propellers on my boat are about two feet behind the transom. Unless I was going in reverse it is hard to imagine how propeller turbulence could affect the transducer that far away.

Now if you are talking about turbulence from the nose cone of the lower unit, that would seem to have an equal effect on either side.

With a clockwise rotating propeller, the upper blade is throwing turbulence to starboard and the lower blade is throwing turbulence to port. The transducer is actually mounted closer to the upper blade than the lower blade.

I don't quite see the reasoning being used in the starboard side recommendation.

jimh posted 02-29-2004 10:29 PM ET (US)     Profile for jimh  Send Email to jimh     
Re the Airmar recommendation--they are probably talking about inboards with a propeller and shaft upstream of the transducer, no outboards where the propeller is downstream of the transducer!
cmarques posted 02-29-2004 10:38 PM ET (US)     Profile for cmarques  Send Email to cmarques     
I have both mounted on the starboard side between engine and swim ladder. Will try to get some pictures in the next day or so. Even with both mounted I haven't used the wheel speed reading only the gps speed. I've been very happy with the unit so far although the base map isn't the most accurate in detail,but the navigation aids (markers, bouys) are dead on. I would like to get a card for it- can't remember which type right now but they are the same as Lowrance uses. I have no problem with the trailer bunks interfering.


Moe posted 02-29-2004 11:34 PM ET (US)     Profile for Moe  Send Email to Moe     
Because with a clockwise rotating propellor the port blade is throwing turbulence up against the functioning bottom of the transducer and the starboard blade is throwing turbulence down on the non-functioning top of the transducer?

FWIW, the Furuno and Garmin manuals show it mounted on the starboard side of an outboard. The Lowrance shows it on either side as good.


jimh posted 03-01-2004 12:44 AM ET (US)     Profile for jimh  Send Email to jimh     
Moe--go look at that VERADO engine underwater video and see if you can find any bubbles two feet in front of the propeller caused by the blade turbulence.
Moe posted 03-01-2004 10:09 AM ET (US)     Profile for Moe  Send Email to Moe     
Jim, are you saying that because there aren't air bubbles there, that an outboard prop doesn't generate turbulence ahead of it that could interfere with a transducer? I just want to be clear about this.


thesarras posted 03-01-2004 12:27 PM ET (US)     Profile for thesarras  Send Email to thesarras     
Thanks for post...pix would be great. On D15, swim platform mounted on port side vice stbd.

The Eagle 320DF uses Navionics XL MMC cards... that would give you more detail on chartplotter. They sound expensive though, so I have not bought one yet. I move around in the Navy alot, so I am worried I will get a limited chartzone that will be useless to me in another year when I move.
Home is where the Navy sends you!

jimh posted 03-01-2004 08:47 PM ET (US)     Profile for jimh  Send Email to jimh     
Moe--are you asking me if I think that from a propeller rotating at several thousand RPM which is directing 50-200 HP of thrust sternward in a stream of water passing by it at 35-50 MPH that air bubbles can somehow be imparted with enough velocity and momentum to carry 24-inches upstream against this flow in a liquid medium whose density is three orders of magnitude greater than air (or maybe more) even though this direction of travel is 180-degrees opposed to the thrust of the propeller and the stream of water?

I just want to be clear about this.

Moe posted 03-01-2004 09:56 PM ET (US)     Profile for Moe  Send Email to Moe     
Jim, I am asking whether your statement about not finding bubbles in front of the Verado prop is meant to indicate that an outboard prop doesn't generate turbulence ahead of it that could interfere with a transducer.


jimh posted 03-01-2004 11:43 PM ET (US)     Profile for jimh  Send Email to jimh     
Verado video notwithstanding (and it is a dandy look at underwater gear in action), I don't think a typical outboard motor operating in forward with the boat moving at any sort of speed could create a situation where bubbles (aerated water) were being directed to a transom mounted transducer.

(If you have the outboard in a well three feet in front of the transducer all bets are off.)

As for Port or Starboard, they both work, and as a survey of fish finder instruction manuals showed, you can be guided to install them either way.

Those Airmar transducers are usually used on larger, deep-water boats, and probably more often than not with inboards, so I really think that is where their comment is directed.

Hey, mount it on port or starboard, it's okay with me, but just don't run the wires through the splash well drains! That cannot be overlooked and will be marked down.

cmarques posted 03-02-2004 07:04 PM ET (US)     Profile for cmarques  Send Email to cmarques     

Here are some pictures of how my transducers are mounted for the Eagle 320df, hope this helps.


thesarras posted 03-03-2004 07:53 AM ET (US)     Profile for thesarras  Send Email to thesarras     

Thanks for posting the pix. There is one good transom shot where I can see the skimmer transducer. Looks like a good clean install. Unless the speedwheel somehow attaches to the skimmer transducer bracket, I only see the transducer mounted. Does the chartplotter function of the Eagles 320DF give you speed boat is travelling? If it does (as I suspect) I don't see the need for cluttering up the transom with a second mounting in addition to the transducer.

Thanks again! Looks like you were at one of the board sponsored get togethers. They look like fun! Hope someday my dad and I can attend one on Cape Cod. He has an 1984 Montauk and I have a 1998 Dauntless 15.

cmarques posted 03-04-2004 07:13 PM ET (US)     Profile for cmarques  Send Email to cmarques     
The paddle wheel is mounted about 10" away from the skimmer. If I knew beforehand I would not have mounted the paddle wheel due to being able to set the unit for GPS or wheel speed or both together. Depends on how you want to use it. When I got mine last year was told all features identical to Lowrance LMS320 but $100 cheaper. If you have a DSC capable radio you need an extra cable with NMEA outputs to replace the current power cable and have to go into the setup to enable the output to send info- just a little FYI that took some time to figure out.
The other pictures were at the Kice Island Rendezvous in nov. We will also be at the Homosassa Rendezvous this weekend- should be a great time again!


thesarras posted 03-04-2004 07:52 PM ET (US)     Profile for thesarras  Send Email to thesarras     
Thanks for the followup. I was sickened to hear the dealer went ahead and mounted the speedwheel w/o checking with me. I too would prefer just the skimmer. At this point, I am probably better off just leaving it now rather than remove it.

Do you find that the Doelfin makes a big difference? I noticed it on your Merc.

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