[Rhodes22-list] Slim & Todd's Engineering Idea

[ed kroposki]

Slim, Todd:
	What you guys need to design is a telescoping mast that works off
electric or hydraulics.  Push a button and up goes the mast with sails
attached.  We have power antennas why not power masts?  I know between the
two of you we will get this accomplished.

Ed K
Greenville, SC, USA
Addendum:  "All it takes is one idea to solve an impossible problem."
- Robert H. Schuller

3/4/2005

-----Original Message-----
From: rhodes22-list-bounces at rhodes22.org
[mailto:rhodes22-list-bounces at rhodes22.org] On Behalf Of Slim
Sent: Saturday, September 03, 2005 11:12 PM
To: Rhodes
Subject: Re: [Rhodes22-list] Engineering Idea

Thanks Todd and you're right--this is not my idea.  As I was raising my mast
to launch in the Apostle Islands, a gentleman watching me told me of a
couple other boats that use the boom for a gin pole.  I like the idea of
parts doing double duty and wondered if we might dispense with at least one
big part--the GB crane.  I'd rather not sail around with it on board, trying
to find a place to stow it.  Our boat is already loaded up with stuff.

I lower the mast to the stern.  But whether I use crane or boom, what about
the quick-release levers on the forward lowers?  If I also got the mast bail
(which I've just ordered) I wouldn't have to mess with disconnecting and
reconnecting ANY shrouds!  That alone would save a lot of time and fuss.
There are a couple examples in the WM catalogue pg. 1022 but the throw is
only an inch or two.  If I could get an 8" throw, I could eliminate two more
parts--the two extensions.

I'd worry about lowering the mast without a crutch, letting it hang there
while we motor under the bridge.  When it's down in that position, that's
when there's the most stress put on everything.  And you'd be sitting in the
cockpit at the helm if it failed--not good.  However, using the boom as a
gin pole, its greater length would mean greater leverage and therefore less
stress on everything.

But thanks for the ideas and the drawings.  I like the cockpit table socket
idea.

Slim

On 9/3/05 6:58 PM, "Todd Tavares" <sprocket80 at mail.com> wrote:

> Slim,
> 
> I think Macgregor has done something like this already. It seems like
> they saw GB's mast raising system and copied it.   I didn't study your
> e-mail in great detail, but are you planning to lower the mast toward the
> bow? Why do all of the extra engineering when you already have a mast
> crane?  Maybe you could make a two piece or folding temporary mast
> crutch.  Make a single pole temporary crutch that would, say fit into a
> wooden block dropped into the cockpit table socket. Or a double pole
> crutch that could be spread and set down on the cockpit seats?
> 
> Set your crane up like normal.   Disconnect the furler/headstay. Connect
> the crane to the foredeck and mast using the stays or a bail on the mast.
> (maybe attach your spreader link thingies?)  Lower the mast unto your
> temporary crutch and motor like heck under the bridge.   You may even get
> away with just lowering the mast and stop it where you need it.  I do not
> know how the GB crane winch works, but can't you stop where ever you want
> and ahve the winch brake hold the mast?  If so, you could have your first
> mate steady the mast, set the brake, and you could go aft to hold the
> mast while she motors under the bridge?
> 
> You would have to do the math to see how far to lower the mast to clear
> the bridge at the highest water mark.   Make the crutch to the correct
> length, and find its best position/ location.
> 
> For ideas, see:  http://www.boats4sail.info/mast.html and attached
> drawings.  Sorry for the crude drawings, but I didn't have a lot of time
> to draw them.
> 
> Todd
> 
> 
> 
> ----- Original Message -----
> From: Slim
> To: Rhodes
> Subject: [Rhodes22-list] Engineering Idea
> Date: Sat, 03 Sep 2005 15:30:18 -0500
> 
>> 
>> Lake Minnetonka, my home waters, is divided into two parts separated by
> a
>> bridge. If I could get under the bridge, it would more than double the
> area
>> in which to sail. I'm thinking of a way to drop the mast quickly to get
>> under the bridge. I'm no engineer so I'm way out of my league here but
> what
>> about this:
>> 
>> Eliminate the GB hoist crane and use the boom for the gin pole. Replace
> the
>> big GB mast crutch with a single pole. Eliminate the 8" shroud
> extensions
>> and replace with lever-operated quick release mechanism like some boats
> have
>> on running back stays and some boats have levers on the upper
>> shrouds--slacking one depending on the tack.
>> 
>> I'm imagining this procedure to take less than five minutes:
>> 
>> 1. Slack the back stay tensioning line.
>> 
>> 2. Disconnect the main sheet from the boom. (No need to remove the
> traveler
>> bar.)
>> 
>> 3. Deploy mast crutch. (Single telescoping pole with "V" on top.)
>> 
>> 4. Disconnect boom at gooseneck and walk the boom forward. (The two
> lines
>> going to the aft end of the boom, the topping lift and the main sail
>> outhaul, stay connected and simply go slack when the aft end of the
> boom is
>> at the foot of the mast.)
>> 
>> 5. Secure the aft end of the boom at or near the foot of the mast.
>> 
>> 6. Disconnect bow stay and insert block and tackle between bow stay and
> the
>> chain plate. (The forward lowers are holding up the mast.)
>> 
>> 7. Connect forward end of boom to the end of the bow stay/block and
> tackle
>> connection.
>> 
>> 8. Throw off quick-release levers on forward lowers.
>> 
>> 9. Lower the mast.
>> 
>> I know the devil's in the details--how to connect the aft end of boom
> to, or
>> near the foot of the mast and how to connect the forward end of the
> boom to
>> the bow stay. The GB hoist winch won't spin if you let go of it whereas
> a
>> block and tackle would run if you let go. (So don't frickin' let go!)
> It
>> could have a cam cleat so you could set it and walk away. The boom is a
> lot
>> longer than the GB crane pole and would provide greater leverage but
> maybe
>> it's TOO long--I haven't measured--although where it hooks on to the
> bow
>> stay doesn't necessarily have to be at the very end of the boom.
>> 
>> I'm just brain storming here but is this feasible?
>> 
>> Slim
>> 
>> __________________________________________________
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