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Has anyone tried moving the speedo to centerline

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Topic: Has anyone tried moving the speedo to centerline
Posted By: jracoffman
Subject: Has anyone tried moving the speedo to centerline
Date Posted: 03 July 2017 at 16:32
All,

I am in the process of doing a significant electronics upgrade, dumping the old SIMRAD instruments on my 2010 H375 and going with new B&G instruments. Sad how outdated and obselete the old electronics are just 7 years later.

One issue I have with the Hanse is that the current position of the speedo/depth transducer is off centerline so you can often get materially different speed readings from one tack to another. Wondering if any one has tried a installing a new speedo at centerline. I am trying to do this, and wondering to what extent I can fit a smaller fitting under the floorboard in the forward cabin which I know doesn't have much clearance, and may require raising the floor an inch or two. How far forward of the keel is that? Other option is to put it in the small compartment under the Vberth just forward of the water tank, but that is awfully close to the bow and likely to come out of the water in heavy seas or chop.

Any advice or previous experience others have had with this is greatly appreciated.
Regards,
James
Gemini (USA 60468)

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James C
Gemini, Hanse 375 #644
USA 60468



Replies:
Posted By: Brufan
Date Posted: 03 July 2017 at 19:45
Leave it where it is.
It is the usual place for speed sensor (as far It factory fitted just at the aft end of V berth)
A small offset from centerline is not a problem


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Bruno

hanse 355 - 57

S/Y Spicy Ginger

White hull, 2 cabins, Volvo D1-30, Selden rig, removable mainsheet track system (modifications done now), Simrad-Jefa autopilot.


Posted By: Johan Hackman
Date Posted: 05 July 2017 at 18:32
Originally posted by jracoffman jracoffman wrote:

Wondering if any one has tried a installing a new speedo at centerline.


It's been irritating me for years that the the speed sensor is mounted on the starboard side of the keel on my 342. When heeling, the speed readings vary between the two tacks a lot. This does not only affect the speed information, it also affects the wind information. True Wind Direction varies 10 to 20 degrees between tacks and it doesn't help that the cups on the wind sensor move slower when the boat heels.

I have been contemplating either moving the speed sensor the way you descibe or replace it with an ultrasonic sensor. The ultrasonic sensor measures at what speed particles in the water moves at a distance from the hull, unlike the paddle wheel that measures the water movement at the surface. If you think about it, the hull is designed (correct me if I am wrong) to give different flows on each side when heeled. I mean, the wing profile theory applies even here, not only when it comes to the sails, the keel and the rudder. But then again, I am not an engineer so feel free to disagree.

I haven't been on many 370s but I recall being on one and that I found the speed sensor under the floor board in the fore cabin. Someone perhaps could fill me in on this?

Johan

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Posted By: iemand
Date Posted: 05 July 2017 at 19:24
On 312/341 they used to put the sensor next to the keel because of the missing hight under the floor boards. On the 370 the sensor is in front of the keel slightly of center (maybe 15cm). In my opinion that doesn't make a difference and is a completely different story to your issue!

BR THomas


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Hanse 312 MJ 2004 - Hanse 370e MJ 2007


Posted By: Peter Russell
Date Posted: 05 July 2017 at 19:27
On the 370 it is indeed in the forecabin nearly on the centreline (probably 300mm offset to port).  I've not noticed a problem - often because it is so fouled it rarely works!

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Peter Russell

Hanse 370 hull 499 "Outnumbered"



http://outnumbered.the-russells.net" rel="nofollow - http://outnumbered.the-russells.net


Posted By: StavrosNZ
Date Posted: 05 July 2017 at 23:49
Unless you are racing why not put the blanking plug in the through hull and use SOG on the plotter for speed.

Eliminates this problem and the need to clean the paddle wheel at intervals.

For cruising its a trouble free solution.


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Stephen
2010 H400, Auckland, New Zealand


Posted By: Johan Hackman
Date Posted: 06 July 2017 at 09:56
SOG is a good substitute for boat speed in water without currents. It will however not be a good substitute when it comes to calculating true wind.

Johan

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http://www.johanhackman.se" rel="nofollow - http://www.johanhackman.se


Posted By: iemand
Date Posted: 06 July 2017 at 10:03
that is indeed the problem with SOG.

Interesting point: Why are all systems calculating the TWS based on speed in the water and not SOG? That would make much more sence to me!


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Hanse 312 MJ 2004 - Hanse 370e MJ 2007


Posted By: Johan Hackman
Date Posted: 06 July 2017 at 10:44
I shall attempt to answer that question.

First of all, it is mathematics.

Velocity is a so called vector, i.e. you don't only tell how fast your going but also in what direction. Look at the wind. You talk about the wind speed. But not only that, you also talk about its direction. For example, you are not just interested in that the wind tomorrow is going to be 10 knots, you will also want to know if its going to be blowing from North or South. The velocity of the wind is therefore a vector.

Now, in a car the direction is implied. The direction is always forward (never sideways) and in relation to the road. Therefore many people think that velocity is just a number and not a vector but it is a vector anyway.

Then you have the speed of your boat. That is also a vector but the first thing you will ask yourself is what is the velocity related to? Is it in relation to the water or is it in relation to the bottom of the sea, i.e. the ground? Boat speed as measured by the paddle wheel is in relation to the water whereas SOG is related to the ground.

When you measure the boat speed the direction is implied. The direction is where the bow points. The wind that your boat creates by moving forward is something I call speed wind for want of a better expression.

Your wind sensor gives you a vector - apparent wind speed (AWS) and apparent wind direction, or angle (AWA). This vector consists of two vectors - the true wind speed (TWS) and true wind angle (TWA), which is the wind blowing across the water - and the other vector that is your boat speed and the implied direction of that vector, i.e. straight forward.

In order to calculate the True Wind (you can't measure it when the boat is moving) you will have to withdraw the Speed Wind from the Apparent wind. This is a complicated mathematical operation done in the wind instruments.

SOG is consequently also a vector. It has a speed, but the direction is not implied to be straight ahead in the direction of th bow. You can actually be sailing six knots sideways if you are in a current.

So SOG cannot be used in that mathematical operation. It can only be assumed to equal to Boat Speed both when it comes to the speed and direction. As soon as the direction is not in the direction of the bow (i.e. when COG is not equal to your heading) the vectors summation will not work.

That's my answer why you don't use SOG to calculate the True Wind.

Johan


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Posted By: iemand
Date Posted: 06 July 2017 at 12:36
Your boat is on a river where the wind is blowing with 20kn in the direction of the river. The tide is running with 2kn in the wind direction. You are doing 8kn thrue the water with the wind and 10kn SOG. Your apparent wind speed will measure 10kn and your system will show 18kn true. If you go back with the engine with 6kn thru the water you will go 4kn SOG. You will measure 24kn AWS and your TWS will show 18kn true.

This simple example shows that the calculation is wrong.



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Hanse 312 MJ 2004 - Hanse 370e MJ 2007


Posted By: Pride of Waterford
Date Posted: 06 July 2017 at 15:04
What are you dumping?
I might be interested in recycling them on my boat.
If you haven't dumped already please let me know what you have thats still working
Many thanks
Jon


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Brod Port Lairge


Posted By: jracoffman
Date Posted: 06 July 2017 at 15:48
I haven't dumped anything and happy to discuss selling my old SIMRAD displays (6 IS20s, 3 of which are COMBIs), BR24 Radar, and NX40 chart plotter. As I was periodically having to replace IS20s, I noticed they are increasingly difficult to find... Feel free to PM me for more specifics and any offer you are willing to make.

James


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James C
Gemini, Hanse 375 #644
USA 60468


Posted By: Pride of Waterford
Date Posted: 06 July 2017 at 17:32
 2 combis and 2 of the 7 or 3 way simnet connectors and a couple of lengths of cable would be useful.
I have a NX40 in good condition but I have noticed there is still a market for those so you should be able to ebay that.
Let me know approx price you want and We can organise paypal payment and shipping as a gift of no commercial value which would make customs easier here.
All best
jon


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Brod Port Lairge


Posted By: Johan Hackman
Date Posted: 07 July 2017 at 09:56
Originally posted by iemand iemand wrote:

Your boat
is on a river where the wind is blowing with 20kn in the direction of the river.
The tide is running with 2kn in the wind direction. You are doing 8kn thrue the
water with the wind and 10kn SOG. Your apparent wind speed will measure 10kn and
your system will show 18kn true. If you go back with the engine with 6kn thru
the water you will go 4kn SOG. You will measure 24kn AWS and your TWS will show
18kn true.

<p ="Msonormal"><span lang="EN-US">This simple
example shows that the calculation is wrong.<o:p></o:p></span>



Why do you mean the calculation is wrong?

Johan

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http://www.johanhackman.se" rel="nofollow - http://www.johanhackman.se


Posted By: iemand
Date Posted: 07 July 2017 at 11:45
Because the wind is blowing with 20kn

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Hanse 312 MJ 2004 - Hanse 370e MJ 2007


Posted By: Johan Hackman
Date Posted: 07 July 2017 at 12:05
I see what you mean. So here's my next "lesson":

I wrote previously that you must ask yourself in relation to WHAT the wind is blowing. In your example the wind is blowing 20 knots in relation to the ground. While on the river you will only experience 18 knots, because then the wind is blowing in relation to the water.

If you change the parametres you will see what I mean. Take away all the land and put yourself in your boat on the ocean. You cannot even see land from where you are, only water. You have no idea what the wind across the nearest land is.

There is a 10 knot Southerly wind and a 10 knot Northerly current, i.e. the wind blows in exactly the same speed and direction as the water is flowing. You will not have any wind at all while there will be a 10 knot wind across the nearest land. Standing on the shore will be windy but drifting in your boat will be windless. That's because one wind information is the wind across land and the other wind across water.

Therefore 18 knots is correct as long as you want the wind across the water, and that is going to be the information you are looking for if you are sailing.

Johan

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Posted By: jracoffman
Date Posted: 07 July 2017 at 13:59
All good discussion here.  Hadn't heard of the ultra sonic option, and may research that.  Since I am racing extensively, AND in an area of heavy currents (Long Island Sound) having STW be very accurate on both tacks is important information for me.  It can very up to a knot from one tack to the other.  I am purchasing a 'shorty' thru-hull that only sticks up about 3 inches, so we will see if we can get it under the floorboard of the forward cabin on my 375 which has very little clearance.  The other issue I am being told is that it needs to be 1-2 feet forward of the leading edge of the keel, so that may push me to put the speedo all the way to in front of the water tank.  Will keep everyone posted.

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James C
Gemini, Hanse 375 #644
USA 60468


Posted By: Johan Hackman
Date Posted: 07 July 2017 at 14:14
James,

I just tried to reply to your post but I get a message that this forum is moderated.

Johan

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Posted By: Johan Hackman
Date Posted: 07 July 2017 at 14:17
Ok, so I shall retry to write the post without upsetting the forum software.

All transducers are made by a company called Airmar. Maybe the fact that I posted a link to their site upset the software so I will ask you to Google it.

You should check their product range and you will probably find a few ultrasonic speed sensors there.

Johan

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Posted By: Johan Hackman
Date Posted: 07 July 2017 at 14:18
My sensor is a Maretron DST100 (depth, speed and temperature) but the user guide is identical to the guide for the Airmar DST800, which I believe is the "triducer" Hanse fits in their boats nowadays.

Johan

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Posted By: Johan Hackman
Date Posted: 07 July 2017 at 14:20
A couple of years ago I looked at a sensor called CS4500 but it does not seem to be in the market anymore.

Johan

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Posted By: Johan Hackman
Date Posted: 07 July 2017 at 14:21
http://www.airmar.com/productdescription.html?id=199" rel="nofollow - http://www.airmar.com/productdescription.html?id=199

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Posted By: Johan Hackman
Date Posted: 07 July 2017 at 14:23
Puuhhh! It took me four posts two rewrite the post that was sent to the Moderator instead of the forum.

Anyway, the link above is to a sensor I find very interesting. I will read about it for sure.

Johan

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Posted By: samuel
Date Posted: 07 July 2017 at 14:46
Many years ago I had 2 paddle wheels fitted on my earlier boat. One each side of the hull.This was because the paddle wheel one side would often come too near the surface as the boat always sailed on its ear.
There was a mercury switch rather like a horizontal egg timer that was pivoted in the middle. When the boat heeled one way the mercury ran to one side & the egg timer tilted & set an electrical connection to one paddle wheel. On the opposite tack the opposite would happen.
Could you have 2 paddle wheels & a change over switch.
 That way you could get 2 wrong readings rather than one correct & one incorrectThumbs Up



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Daydream Believer- Hanse 311- No GBR9917T- Bradwell Essex


Posted By: High Time
Date Posted: 07 July 2017 at 17:08
True wind is the wind speed and direction measured by a stationary (wrt the ground) sensor. 

The only way to fully allow for all vectors affecting the motion of the boat is to subtract the SOG vector (i.e. including COG) from the apparent wind vector.

Any mathematical function using STW will not always eliminate all the motion of the boat (current, leeway etc).

It is disappointing that only high end wind instruments allow the option to use SOG/COG to give TWS/TWD.


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Roger

High Time (415 #038)


Posted By: Johan Hackman
Date Posted: 07 July 2017 at 17:21
On a boat, True Wind is the wind that blows across the water. The electronics have traditionally been designed to show you this from the beginning.

If you want the wind in relation to the ground you need to find another name for it. It will however be less helpful kind of information when you are sailing.

Mathematically it is not enough to subtract the velocity over ground from the apparent wind. You will also have to make a relation between the boat's centreline and the rest of the calculation, so to speak.

I have been discussing this for years, both in this forum and Panbo.com but I have had a hard time convincing people I am right. Either I am the new-born Einstein or the village idiot.

Johan

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Posted By: High Time
Date Posted: 07 July 2017 at 17:29
Originally posted by Johan Hackman Johan Hackman wrote:


There is a 10 knot Southerly wind and a 10 knot Northerly current, i.e. the wind blows in exactly the same speed and direction as the water is flowing. You will not have any wind at all while there will be a 10 knot wind across the nearest land. Standing on the shore will be windy but drifting in your boat will be windless. That's because one wind information is the wind across land and the other wind across water.

Therefore 18 knots is correct as long as you want the wind across the water, and that is going to be the information you are looking for if you are sailing.

Johan

Johan

In your example above, the TWS is always 10 knots. It's the AWS that is zero, assuming your STW is also zero. As soon as you have some motion relative to the water, your AWS will not be zero but the TWS will remain at 10 knots.


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Roger

High Time (415 #038)


Posted By: Johan Hackman
Date Posted: 07 July 2017 at 17:44
If the water and the air both are moving at the same speed and in the same direction there will be no wind. You will not be able to sail.

You could motor and then create an apparent wind that is the same speed as your boat speed through the water, but in the exact opposite direction.

If you are out there with no wind you could still see flags on the shore fluttering. There will be wind on the shore but not where you are.

If you are walking at the speed of 10 knots on the pavement your velocity in reference to the ground will be 10 knots. If you are holding your girlfriend's hand and she is walking at the same speed and direction you will not loose her. The velocity away from her is zero.

Johan

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Posted By: High Time
Date Posted: 07 July 2017 at 20:54
Johan

Everything you say is correct. However, it doesn't alter the fact that the TWS in your example is always 10 kts whether you are sailing, motoring or walking your girlfriend..

The apparent wind changes dependent on the motion of the boat (relative to the ground) and it is really only the apparent wind that is of any use to the skipper when sailing. However, knowing the true wind can be useful when entering a marina, lock or other slow speed manoeuvre, or maybe planning ahead for a sail change.


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Roger

High Time (415 #038)


Posted By: High Time
Date Posted: 07 July 2017 at 21:13
Hi Johan

I've just found an interesting paper that explains (more clearly than I could), the maths behind the calculation of true wind on a moving boat.

http://davidburchnavigation.blogspot.co.uk/2013/04/true-true-wind-from-apparent-wind.html" rel="nofollow - http://davidburchnavigation.blogspot.co.uk/2013/04/true-true-wind-from-apparent-wind.html

Just to bring us back to the original subject of this thread, the last paragraph of the paper above suggests a simple way to check if your speedo is accurate on both tacks.





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Roger

High Time (415 #038)


Posted By: Johan Hackman
Date Posted: 07 July 2017 at 22:38
Roger,

Thanks for the link to the article. It proves that you are right but then again, the author of the article is wrong.

It's all about naming things. What is True Wind, really? As I stated clearly before, it is in relation to whatever object the air is moving that should determine the name of such wind. To me, and the instrument makers, the name "True wind" is referring to a mass of air moving across a mass of water. If you want a "Truer Than True Wind" you might find it truer to tell the wind across something that is not moving, as water sometimes does, such as the parts of the Earth that stick out of the oceans. Let's call it the "ground".

To call a mass of air moving an "apparent" wind is apt as it refers to whom it is apparent. To me, and so far the instrument makers, it is the wind that hits our faces when we are sailing. It consists of the air moving across the water together with the wind the journey across the water we sail generates, i.e. the speed wind that I referred to earlier.

Now, the author of the article calls the wind that you perceive on the water without the wind generated from the boat speed "apparent wind". It is "apparent", and very real (or "True", if you like) to someone who is disconnected from land but why not call it "perceived wind"? (Did I just invent the abbrevation PWS and PWA- Perceived Wind Speed and Perceived Wind Angle?) What I am saying is that if you call one wind one thing, you should find another name for another wind. The confusion should not about how to name different things.

I know I mentioned earlier that I have been discussing this earlier, and one of the places is Panbo.com. The editor of that blog (and whom I admire a lot) is Ben Ellison. After having very long discussion and a few almost heated arguments in the forum at his blog he wrote a blog post where he suggested True Wind should be renamed or redefined. I used the better part of this afternoon to find this blog post and I chuckled when I saw when the first commenter of the article you linked to was...

Johan

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Posted By: Johan Hackman
Date Posted: 07 July 2017 at 23:06
So if you follow the link you posted and check the link Ben provides,
http://www.panbo.com/archives/2013/03/the_equinox_celestial_mechanics_pesky_true_wind.html" rel="nofollow - http://www.panbo.com/archives/2013/03/the_equinox_celestial_mechanics_pesky_true_wind.html
, you will find my name in the article. I think this was the blog post I was looking for this afternoon.

Johan

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Posted By: Johan Hackman
Date Posted: 07 July 2017 at 23:20
I find it amusing that if I look at the link you provide and follow the first commenter's suggestion to a link the first commenter is - me!

Johan

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Posted By: Johan Hackman
Date Posted: 07 July 2017 at 23:39
I must say I am having a ball reading my own comments in that thread! I should go to bed but I pour myself a glass of red wine and have a good time.

I turns out I have already invented another type of wind - the "Hobby Wind"!!! This was already in 2013!!

Johan

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Posted By: High Time
Date Posted: 08 July 2017 at 09:44
Johan

It's becoming clear to me also that the problem is with names not principles or maths. True Wind, I think everyone agrees, is defined as wind speed and direction relative to the ground. 

The confusion has arisen amongst sailors because instrument makers have chosen to use the term True Wind to mean wind speed/direction relative to the water. Elsewhere it has been suggested that this should be termed Water Wind to avoid the confusion.

Instrument makers originally provided Water Wind info because it could be easily derived in the wind instrument if STW data was added.

With the advent of networked GPS SOG/COG data on most modern boats it is now possible to derive True Wind (relative the ground) and I suspect in a few years this will become generally available on mainstream wind instruments and plotters. As a social, rather than a racing, sailor, I believe True Wind is (marginally) more useful than Water Wind.

PS The link you provide to Panbo doesn't work for me. Does it still work for you?


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Roger

High Time (415 #038)


Posted By: Johan Hackman
Date Posted: 08 July 2017 at 10:45
Roger,

I reposted the link so it works now.

Like I wrote above, I had a ball yesterday night re-reading all the discussions about True Wind I have been involved in. It's been a few years now and I kind of miss the late nights when I was trying to find ways get my points across. I also remember how difficult it was and I see that I in this thread start to walk in my own foot steps. Therefore I have decided to retire from the True Wind discussion.

Johan

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Posted By: High Time
Date Posted: 08 July 2017 at 15:47
Hi Johan

Thanks for re-posting the link. I follow Panbo as I am particularly interested in electronics and navigation etc. but missed the referenced thread the first time around. It's interesting to see the discussion has been doing the rounds for several years now (and to note that Ben's position on True Wind is similar to mine  Thumbs Up).

I think we are actually in agreement that it is really only a terminology issue, so I, too, will bow out gracefully from this thread.

Fair winds.


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Roger

High Time (415 #038)


Posted By: StavrosNZ
Date Posted: 09 July 2017 at 21:47
All very fascinating and technically correct but again i have upgraded my instruments from Simrad to B&G Triton. For cruising (we have low tidal flows and falls) i use SOG, no paddle wheel to remove and clean, no variation on either tack and the impact on TWS is minimal based on my observations. For cruising its low maintenance trouble free solution. 

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Stephen
2010 H400, Auckland, New Zealand


Posted By: iemand
Date Posted: 10 July 2017 at 07:09
How is your system calculation TWS without Speed thru the water? It must be the same as AWS?!

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Hanse 312 MJ 2004 - Hanse 370e MJ 2007


Posted By: High Time
Date Posted: 10 July 2017 at 10:17
Originally posted by StavrosNZ StavrosNZ wrote:

For cruising (we have low tidal flows and falls) i use SOG, no paddle wheel to remove and clean, no variation on either tack and the impact on TWS is minimal based on my observations. For cruising its low maintenance trouble free solution. 

I would do the same but the speedo (paddle wheel) also includes the depth sensor which I can't do without! I think I would also lose TWS/TWD as this needs the STW input (IS20 and NSS8 system).

Does the Triton wind system give TWS with reference to SOG (maybe as an option)?


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Roger

High Time (415 #038)


Posted By: Johan Hackman
Date Posted: 10 July 2017 at 10:34
I can confirm that you can use SOG as Boat Speed on B&G Triton displays. I don't know whether this will be used to calculate True Wind, but it seems logical.

I will not tick that box because of what I believe in and what I have written about in this thread.

Johan



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Posted By: StavrosNZ
Date Posted: 12 July 2017 at 22:12
I leave the paddle wheel in the hull as it has sea temp sensor built in and it still provides True wind data but use SOG on instruments...............for cruising, trouble free.

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Stephen
2010 H400, Auckland, New Zealand


Posted By: jracoffman
Date Posted: 16 July 2017 at 19:27
Well, this has certainly been an interesting thread. Given I am doing a lot of distance racing, and in an area where there is typically a fair amount of current, I did move forward with moving the speedo to centerline. I was able to find a 'shorty' transducer that just barely fits under the floorboard in the forward cabin. I may have to get the router out to give a hair more clearance for the floorboard. Now I will have accurate speed readings through the water on both tacks (it could vary up to 1kt), which will also translate to more accurate wind readings.

Sadly, when I pulled up that floorboard, we found evidence of the hull flexing, and the tabbing from the hull to the grid being damanaged. I will start another thread, but curious if anyone else has experienced this. I am told this could be upwards of 15 hours of work. Ugh.





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James C
Gemini, Hanse 375 #644
USA 60468


Posted By: jracoffman
Date Posted: 16 July 2017 at 19:42


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James C
Gemini, Hanse 375 #644
USA 60468


Posted By: Johan Hackman
Date Posted: 17 July 2017 at 17:08
James,

Is the speed sensor on your boat on the port side? On mine it is on the starboard.

I am curious to know what speed sensor you found that doesn't stick up so much. Do you have a link to the product site?

I am also very curious how your new solution works. Please keep us posted.

As for the cracks, I am sad to see that this has happened to you. I think my boat looks similar with the outer mould (the hull) and the inner mould (the frame and the interior) are joined together in this area. I think this would further complicate installing a speed sensor since you will have to drill through two layers of plastic.

I have not experienced any cracks in this are and can sadly be of no help here.

Johan

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Posted By: jracoffman
Date Posted: 17 July 2017 at 18:43


Here are pics. It's the Airmax ST300 Short Speed Transducer.. It just barely fits under the floorboard in the forward cabin, and is now perfectly at centerline. We will use a router on the underside of the floorboard just where the senor is to give a bit more clearance.

The person who did the electronics install said Hanse couldn't have picked much worse of a spot to put the speedo with the exception have having it further aft..

Will keep folks updated on how the rest of the electronics installation goes and improved accuracy. Will start a new thread on the hull flexing. No word back from Hanse on the recommended repair or if any might be covered under warranty.


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James C
Gemini, Hanse 375 #644
USA 60468


Posted By: jracoffman
Date Posted: 17 July 2017 at 18:45
And to answer your question, the speed sensor was originally on port. Now we have a separate depth and temp sensor where the old unit was that did depth, speed and temp. Both have flush mounts too, so nice and smooth on the bottom of the hull.

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James C
Gemini, Hanse 375 #644
USA 60468


Posted By: factorygirl
Date Posted: 02 August 2017 at 23:24
Hi! I have moved my Simrad/Airmax tridata transducer to the centerline, just behind the watertank (Hanse 375, 2010). It was quite easy and it works perfect. I did it because the depthsounder didn t work and someone in this forum said that it could be because the transducer were too close to the T-keel-bulb.
Runar, Factory Girl


Posted By: jracoffman
Date Posted: 03 August 2017 at 16:45
Sounds like we have sisterships. While I didn't have the depth issue, having the speedo under the floorboard in the forward cabin, exactly centerline and far enough forward of the keel makes a huge difference.   For someone who sails in a lot of current, it's great to have an accurate speed data. Using the new shorty speedo had just enough clearance that I didn't even have to raise or alter the floorboard. Had about a quarter inch of clearance.


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James C
Gemini, Hanse 375 #644
USA 60468


Posted By: factorygirl
Date Posted: 03 August 2017 at 21:49
Originally posted by jracoffman jracoffman wrote:

Sounds like we have sisterships. While I didn't have the depth issue, having the speedo under the floorboard in the forward cabin, exactly centerline and far enough forward of the keel makes a huge difference.   For someone who sails in a lot of current, it's great to have an accurate speed data. Using the new shorty speedo had just enough clearance that I didn't even have to raise or alter the floorboard. Had about a quarter inch of clearance.
A little cheaper the way i did it, using the same transducer. Did only buy one new surronding tube. Left the old with a plug in. My Factory Girl is #704. Bought her in 2014. Wonderful boat with some annoying issues, the one left now is mainly the wet cocpit-lockers (including the one for the autopilot) on the cocpit floor. Difficult to make it better.



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