[Public-List] Radar - self levelling mast mount

John Birch Sunstone at cogeco.ca
Tue Apr 6 14:08:39 PDT 2010


Hi George,

I believe the radar beam is 25 degrees up & down combined, thus being 12.5
Degrees on the down plane (which is what matters for brains baking purposes)

A person working the foredeck or on the Windward rail under the conditions
that would cause extreme heel you cite will likely be in a crouched
position, to seated, so I doubt there is much risk .

You could of course install an angle limiter on the radar leveler so that it
would never risk the crew.

Albergs sail best to weather at between 15-25 degrees, after which you are
trading a lot of leeway for heel.

I see you are from Peter MacKay territory, truly great sailing and living
country.

Sounds like a great project.

Have fun

Best

John



> ----- Original Message ----- 
> From: <salty at ns.sympatico.ca>
> To: "Alberg 30 Public List -- open to all" 
> <public-list at lists.alberg30.org>
> Cc: "John Birch" <Sunstone at cogeco.ca>
> Sent: Tuesday, April 06, 2010 12:01 PM
> Subject: Re: [Public-List] Radar - self levelling mast mount
>
>
>> John:
>>
>> Thanks.  I did a quick sketch, and at a 30 degree heel it looks like a 
>> unit
>> 10 feet above deck would still clear a foot or so above the head of 
>> standing
>> crew on deck, assuming a 25 degree vertical beam.    Also, the distance
>> between the crew member on the higher side and the antenna would be 
>> greater
>> than what I understand is the minimal safe distance for short intervals.
>>
>> This would probably be sufficient tolerance.
>>
>> Other comments would be welcome.
>>
>> George
>>
>> ---- John Birch <Sunstone at cogeco.ca> wrote:
>>> Hi George,
>>>
>>> All I know is what Raytheon told me. The duration of somebody on the
>>> windward deck in those conditions is slim and the height of the unit 
>>> above
>>> the deck plane is still sufficient unless you plan to sail for extended
>>> periods at 45-55 degrees heel it shouldn't be a problem.
>>>
>>> It will still be much higher than if mounted on a pole and the power 
>>> draw
>>> won't allow you to run the unit all the time anyway.
>>>
>>> Best
>>>
>>> John
>>>
>>>
>>> ----- Original Message ----- 
>>> From: "George White" <salty at ns.sympatico.ca>
>>> To: "Alberg 30 Public List -- open to all" 
>>> <public-list at lists.alberg30.org>
>>> Sent: Tuesday, April 06, 2010 7:51 AM
>>> Subject: Re: [Public-List] Radar - self levelling mast mount
>>>
>>>
>>> > Thanks.  My concern with putting it that low would be that the 
>>> > combination
>>> > of a significant heel angle of the boat and the scanner being level 
>>> > the
>>> > pulse would hit someone on the windward deck?
>>> >
>>> > George
>>> > ----- Original Message ----- 
>>> > From: "John Birch" <Sunstone at cogeco.ca>
>>> > To: "Alberg 30 Public List -- open to all"
>>> > <public-list at lists.alberg30.org>
>>> > Sent: April 5, 2010 8:36 PM
>>> > Subject: Re: [Public-List] Radar - self levelling mast mount
>>> >
>>> >
>>> >> Hi George
>>> >>
>>> >> Suggest you put it about 1/3 distance below the spreaders. This will 
>>> >> give
>>> >> you a much better opening between the forestay and mast for tacking 
>>> >> the
>>> >> Genoa. And you are not really losing any meaningful range for the 
>>> >> radar,
>>> >> plus you are reducing the top-hamper of the weight aloft 
>>> >> considerably.
>>> >>
>>> >> It will be high enough so you don't bake your brains with the 
>>> >> microwaves
>>> >> either.
>>> >>
>>> >> That is where Raytheon suggested I mount mine on my A-37 before I 
>>> >> canned
>>> >> the whole idea for a while anyway. (Money & power draw were the 
>>> >> reasons.)
>>> >>
>>> >> Just a suggestion anyway
>>> >>
>>> >> Best
>>> >>
>>> >> John
>>> >>
>>> >>
>>> >> ----- Original Message ----- 
>>> >> From: "George White" <salty at ns.sympatico.ca>
>>> >> To: "Alberg 30 Public List -- open to all"
>>> >> <public-list at lists.alberg30.org>
>>> >> Sent: Monday, April 05, 2010 6:52 PM
>>> >> Subject: [Public-List] Radar - self levelling mast mount
>>> >>
>>> >>
>>> >>> Does anyone have experience with Scanstruct self levelling mast 
>>> >>> radar
>>> >>> mount?
>>> >>>
>>> >>> Also, should additional ballast be added to compensate for the 
>>> >>> weight of
>>> >>> a 21 pound radar mounted neaar the spreaders?  If so, how or where
>>> >>> should ballast be added?
>>> >>>
>>> >>> George
>>> >>>
>>> >>> Close Harmony
>>> >>> ----- Original Message ----- 
>>> >>> From: "Derrick Serrer" <cptn_derrick at yahoo.ca>
>>> >>> To: "Alberg 30 Public List -- open to all"
>>> >>> <public-list at lists.alberg30.org>
>>> >>> Sent: February 22, 2010 10:39 PM
>>> >>> Subject: [Public-List] (no subject)
>>> >>>
>>> >>>
>>> >>>> Hello everyone,
>>> >>>> Just wondering if anyone has ever given any thought to adding a 
>>> >>>> radar
>>> >>>> arch on their A30? I am contemplating the positioning of my radar 
>>> >>>> unit
>>> >>>> and eventually solar panels and an arch seems to be a logical 
>>> >>>> choice.
>>> >>>> If anyone out there has one, I would love to see pictures.
>>> >>>> Thanks
>>> >>>> Derrick
>>> >>>> #127
>>> >>>>
>>> >>>>
>>> >>>>
>>> >>>>
>>> >>>> __________________________________________________________________
>>> >>>> Get the name you've always wanted @ymail.com or @rocketmail.com! Go 
>>> >>>> to
>>> >>>> http://ca.promos.yahoo.com/jacko/
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>>> >>>>
>>> >>>
>>> >>>
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>>> >>
>>> >>
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> 



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