[PSUBS-MAILIST] launch rollers

Thu Jul 24 13:11:37 EDT 2014

James,
You are getting very close, move the pivot point as far ahead as possible, then lengthen the ramps so the sub always sits on the ramps.  When the sub rolls back with the electric winch holding it, the entire ramp and sub will tilt down with gravity.   The system you have there is still a bit complex.  The Jacks are not so good because you have to lower them at the same rate, plus you don't need them at all.  
Your trailer is ideal for this conversion.  Put a pivot point right above the back axel, build a ramp about 12 feet long.  park the sub on the first 6 feet of ramp with 6 feet or so extending back from the sub.  When the sub roll back it will tip the ramp and your away.  mount your tail lights to the end of the ramps(deck)
Hank 

On Thursday, July 24, 2014 12:48:34 PM, James Frankland via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Hi Hank\All,

Have a look at this pic.  This is my idea for lowering the sub off the trailer.  

Two 2.5m pivoting ramps that attach to the back of the trailer and are connected together at the end with a bar.  
Two legs to support the back of the trailer.
Two 3000kg jacks, one each side.

Sub could be rolled onto the "extension" and then lowered down using the jacks.  Sub is then wheeled off\on using a 3000kg winch. 

The drawing is to scale and shows an angle of 11 degrees.

What do you think?  Its open to suggestions of course.

Many thanks
James

On 22 July 2014 14:41, James Frankland <jamesf at guernseysubmarine.com> wrote:

Hi Hank.
>I like it.  Sounds like a potentially good idea.  I'll give it a bit of thought and draw a few things up.  Any suggestions\ideas from anyone welcome. 
>
>Thanks
>James
>
>
>
>On 22 July 2014 14:02, hank pronk via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>
>Hi James,
>>Right I remember you asking about that now.  The problem with jacking up the front of the trailer is, if you disconnect from the tow vehicle, you got no way to hold her back properly.   
>>My idea with the tilting C channel is to make the channels like a tilting deck.  The sub rolls back a bit and the balance point lets the C channels tip creating a tilting deck so to speak. Your ramps can extend from the C channels creating a long smooth ramp.  You would need a way to hold the tilting C channels from dropping out of control when the sub is completely off the trailer.  
>>You can possibly hinge the C channels right behind the rear axel cross member thus making it very clean and compact. 
>>This can all be accomplished the same way that a gravity tilt deck trailer works.   
>>Hank 
>>
>>
>>
>>On Tuesday, July 22, 2014 8:48:09 AM, James Frankland via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>  
>>
>>
>>Hi Hank,
>>
>>I was aware of the tilting issue.  The plan is to have reasonably long ramps to minimise the tilt and also jack up the front of the trailer to meet the angle.  That was why I was asking about hydraulic rams etc a week or so ago.  In the end I think you suggested just jockey wheels which is what im going to go for.   Well, that the idea but is always open to suggestions.  Can you clarify your c channel tilting idea?   
>>Im not sure what you mean.  Might be better?  
>>ps: The ramps are going to be c channel anyway to stop the boat sliding off sideways.
>>
>>
>>
>>
>>
>>
>>On 22 July 2014 13:08, hank pronk via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>
>>Hi James,
>>>I am worried about your set up with the rollers.  If I understand it, you will have a horizontal trailer deck with ramps on an angle to the ground.  With that many rollers it will be dangerous to transition from the horizontal deck to the angled ramps.  When the sub rolls back, eventually it will be at the balance point and tilt to match the ramp angle.  At the point the sub will be on only two rollers.  If the two rollers happen to be at the transition point where the deck meets the ramps, the sub will turn violently and I mean violently.  It could be dangerous.  There are a few solutions, you can make a tilting track with C channel that tilts with the sub so all the wheels are in contact all the time.  Another solution is to use only four wheels, or best of all a tilt deck trailer.  I went with four large wheels on my cart for these reasons. With four wheels the sub is never at a tipping point.   
>>>Hank 
>>>
>>>
>>>
>>>On Tuesday, July 22, 2014 5:34:36 AM, James Frankland via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>>  
>>>
>>>
>>>Hi Hank,
>>>
>>>Yes, the idea is to make ramps that the sub can be winched down off the trailer.  
>>>Regards
>>>James 
>>>
>>>
>>>
>>>On 22 July 2014 02:48, hank pronk via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>>
>>>James,
>>>>Love the rollers, they look real good.  Are you going to have a tilting track that the rollers run in?   
>>>>Hank
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>>>>
>>>
>>>
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>>
>>
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> 

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