[Public-list] Travellers...Propane Tank
Gordon Laco
mainstay at csolve.net
Wed Mar 30 12:45:09 PST 2005
Hi Roger -
I think you got it all right - you would enjoy reading C.A.Marchaj's book
"the HydroAerodynamics of Sailing" Great book. He wrote another one more
recently called "Seaworthness, the forgotten factor" The later is less on
the science of what is happening than on why some designs of boats are
makedly better seaboats than others. The Alberg 30 looks about the best.
Cheers - Gord #426 Surprise
> Mike Lehman
> ~~~_/)_/)~~_/)~~~
> Wrote;
> "At least the forward water tank is not in the overhang of the boat."
>
> Roger replies;
>
> Mike,
>
> As the Budweiser ad says, "true."
>
> In a never ending quest to confuse myself (and learn just enough to be
> dangerous), I have been reading up on dynamic loading and discovered that,
> unlike static loads where the moment arm is weight times length (from center
> of buoyancy), the moment calculation for dynamic loads is weight times the
> length SQUARED. So, if the fore/aft center of buoyancy is 16' aft (pretty
> darn close to the middle of the boat), a full water tank (30 gal @ 7 lbs)
> has a dynamic moment arm of 210 lbs. times about 8.75 feet squared or a
> whopping 16,000 lbs. If a 25 lb propane tank is located all the way aft,
> the moment arm would still be about 5,000 pounds. This is a scary problem;
> so much so, I have decided to saw off 8 feet from each end of my boat, which
> means I now have to completely rethink the layout of the main cabin!
>
> While keeping the fore/aft weight near the middle is desirable to prevent
> "hobbyhorsing," it gets more confusing because the opposite seems true for
> transverse weight distribution. The dynamic stability (ability for boat to
> resist wind gusts, side wave impacts, roll going downwind) improves as the
> roll moment of inertia (weight times square of distance outboard from center
> of gravity) goes up. Of course, with our boats, it isn't possible to move
> weight outboard without moving it up which raises the center of buoyancy,
> which compromises the static stability, which confuses me even more, which
> makes me want to get back inside "the box" and take a nap after, of course,
> bolting the engine to one side of the boat amidships and the water tank to
> the other.
>
> Mike Meinhold, did I get any of this even close to right?
>
>
> Roger Kingsland
> Chief Boat Boy, Rubber/Scraper, Numbers Cruncher, Source of Confusion and
> Check Writer
> Alberg 30 #148, PERFECT intentions
> N40-33.92, W79-51.25
>
> "You don't have to think outside of the box, but it doesn't hurt to peek
> over the edge once in a while."
> Leonardo Da Vinci (or somebody like that)
>
>
> ----- Original Message -----
> From: "Mike Lehman" <sail_505 at hotmail.com>
> To: <public-list at alberg30.org>
> Sent: Wednesday, March 30, 2005 8:24 AM
> Subject: Re: [Public-list] Travellers...Propane Tank
>
>
>> At least the forward water tank is not in the overhang of the boat.
>>
>>
>>
>> Mike Lehman
>> ~~~_/)_/)~~_/)~~~
>>
>>
>>
>>
>> ----Original Message Follows----
>> From: "Roger L Kingsland" <rkingsland101 at ksba.com>
>> Reply-To: Alberg 30 Public List -- open to all <public-list at alberg30.org>
>> To: "Alberg 30 Public List -- open to all" <public-list at alberg30.org>
>> Subject: Re: [Public-list] Travellers...Propane Tank
>> Date: Tue, 29 Mar 2005 14:32:41 -0500
>>
>> Mike,
>>
>> I agree with you on the weight thing and got an aluminum anchor (has
> anyone
>> heard of/used aluminum chain?) and plan to abandon the forward water tank
>> for the same reasons. I also kicked around the idea of a fuel tank
> (diesel)
>> under the aft portion of the main cabin sole (double benefit of moving
>> weight toward the center and getting it lower) but that got poo pooed big
>> time so I stuck it under the cockpit sole.
>>
>> To my mind, best reason not to do gas is the kaboom thing. Why blow up,
>> when there are so many other ways for the amateur sailor (especially this
>> one) to mess up.
>>
>> Roger
>>
>>
>> From: "Mike Lehman" <sail_505 at hotmail.com>
>> To: <public-list at alberg30.org>
>> Sent: Tuesday, March 29, 2005 1:01 PM
>> Subject: Re: [Public-list] Travellers...Propane Tank
>>
>>
>>> This would work. You would need to keep it sealed and separate from the
>>> locker, which I believe you plan to do. Having said that, I would not
>>> consider this as a project on my boat eventhough I enjoy cooking on a
> hot
>>> stove. IMHO, it would adversly affect the performance of the boat by
>> placing
>>> that much weight in the overhang (unsupported) portion of the boat.
> This
>>> would be like having someone standing on the aft deck while sailing and
>>> place to much weight on the ends of the boat, exactly the position
>> inwhich
>>> you are trying to keep lightweight.
>>>
>>>
>>>
>>> Mike Lehman
>>> ~~~_/)_/)~~_/)~~~
>>>
>>>
>>>
>>>
>>> ----Original Message Follows----
>>> From: "Roger L Kingsland" <rkingsland101 at ksba.com>
>>> Reply-To: Alberg 30 Public List -- open to all
> <public-list at alberg30.org>
>>> To: "Alberg 30 Public List -- open to all" <public-list at alberg30.org>
>>> Subject: Re: [Public-list] Travellers...Propane Tank
>>> Date: Tue, 29 Mar 2005 09:35:43 -0500
>>>
>>> Andy,
>>>
>>> I had a crazy idea for propane storage that goes something like this;
>>> - get (or make) a FG cylinder with an inside diameter equal or bigger
>> than
>>> access port mentioned below;
>>> - fit it inside the lazarette locker (outboard on the side opposite
>> engine
>>> exhaust) running fore/aft with the aft end a few inches lower than the
>>> forward end lower (might have to cut it crosswise);
>>> - fiberglass it to the locker sides at the bulkhead under the traveler
>> and
>>> at the transom
>>> - pressure test the FG install;
>>> - cut ventilation hole(s) through transom at low point of the cylinder;
>>> - cut circle and install access port in traveler bulkhead through which
>> tank
>>> will be installed (from cockpit);
>>> - run all those hoses, switches, regulators etc.;
>>> - to fasten tank in cylinder, place wood "skids" at third points with
> top
>>> one wedge shaped and removable (will probably need to cut off mounting
>>> brackets on horizontal propane tank);
>>> - if you are a gourmet cook (or love hot showers), do it again on the
>> other
>>> side of the lazarette and have a back up tank (need to check if there
> are
>>> any regs. RE distance from propane vent and engine exhaust, could be a
>>> "kaboom" problem).
>>>
>>> The idea is to separate a portion of the lazarette from the hull and
>>> ventilate it directly to the outside. Of course, the idea only works
> if
>> the
>>> FG cylinder inside the lazarette remains air tight and I don't know if
>> hull
>>> flex will degrade the connection between the cylinder and
>> bulkhead/transom.
>>> Perhaps use a FG cylinder thin enough to flex with the hull?
>>>
>>> Oh great sages of Albergdom, please opine. Any merit, or just another
>> Krazy
>>> Kingsland Kaper.
>>>
>>> All the best,
>>>
>>> Roger
>>>
>>> Roger Kingsland
>>> Chief Boat Boy, Rubber/Scraper, Thinker of Odd Ideas and Check Writer
>>> Alberg 30 #148, PERFECT intentions
>>> N40-33.92, W79-51.25
>>>
>>> "You don't have to think outside of the box, but it doesn't hurt to
> peek
>>> over the edge once in a while."
>>> Leonardo Da Vinci (or somebody like that)
>>> ----- Original Message -----
>>> From: "Andrew M Shaw" <andymshaw at juno.com>
>>> To: <public-list at alberg30.org>
>>> Sent: Monday, March 28, 2005 5:31 PM
>>> Subject: Re: [Public-list] Travellers...
>>>
>>>
>>>> Gordon,
>>>> I'll run down to the boat and take a look for you.
>> Wanted
>>>> to see about placement of my new propane tank anyway.
>>>>
>>>> Andy
>>>>
>>>>
>>>> On Mon, 28 Mar 2005 16:24:01 -0500 Gordon Laco <mainstay at csolve.net>
>>>> writes:
>>>>> No problem - but I will back on mine before then - I was hoping to
>>>>> order a
>>>>> new traveller today so that it would come before I went away.
> Can't
>>>>> wait to
>>>>> get on the water. We took the cover off on Friday, a sure way to
>>>>> make it
>>>>> snow one more time!
>>>>>
>>>>> Gord
>>>>>
>>>>>> Gord,
>>>>>>
>>>>>> Thank you sir. If you can hold off until the end of the week. It
>>>>> is raining
>>>>>> here, better than snow off course. We will be working on the
> boat
>>>>> at that
>>>>>> time.
>>>>>>
>>>>>> Stephen
>>>>>>
>>>>>> -----Original Message-----
>>>>>> From: public-list-bounces at alberg30.org
>>>>>> [mailto:public-list-bounces at alberg30.org] On Behalf Of Gordon
>>>>> Laco
>>>>>> Sent: Monday, March 28, 2005 4:18 PM
>>>>>> To: Alberg 30 Public List -- open to all
>>>>>> Subject: Re: [Public-list] Travellers...
>>>>>>
>>>>>> Hi there -
>>>>>>
>>>>>> That's an easy one... 14' aft, 12' forward.
>>>>>>
>>>>>> Now will you tell me how long my traveller is? ;)
>>>>>>
>>>>>> Gord
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>> Gord,
>>>>>>>
>>>>>>> Question, what was the draft on the ship used in Master and
>>>>> Commander?
>>>>>>>
>>>>>>> Thanks,
>>>>>>> Stephen
>>>>>>>
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