Rib layout for USS Des Moines
Last Post 12 May 2009 12:11 PM by brownjm74. 21 Replies.
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radollar2000User is Offline
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19 Jan 2009 01:43 PM

Okay so here is the rib layout that I'm proposing to cut and I thought I get feed back from my elders in this field.  So basically I was hoping all you old guys could give me some of your thoughts on what I need to change. All this is of course in lieu of me actually fielding my boat and provideing yet another target for ya'll to sink forth with. So with out further adu:...hmmm well it seems I can't figure out how to upload pictures so I'll just put it in writing. USS Des Moines has 59.75" length minus 3" and 16 3/8" ribs, leaving 50.75". The first 6 ribs in the bow are 2" apart, the 7 mid-ship ribs are aproximatly 3.45" apart, and the remaining 3 ribs in the stern are 4" apart. There is a stringer along mid-ship which ends 11" from the bow and 11.75" from the stern. As soon as I figure out how to post pictures I will do so, but until then I hopes this gives an idea what my rib layout looks like. Thanks!

Greg McFaddenUser is Offline
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19 Jan 2009 03:21 PM

You may need to try your picture post again...  I know the pictures do not show up for me...

 

 

radollar2000User is Offline
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19 Jan 2009 04:19 PM

okay so how exactly do I do that I haven't been able to get any pictures up. I click on the insert image button thingy and it asks me for a URL. I just put the Pics on Facebook, but that didn't work so I'm at a loss.

Greg McFaddenUser is Offline
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19 Jan 2009 04:49 PM

facebook does not allow direct linking...  most places dont.  You can use picasa or you might try the attachments option below the text editor portion of the post...  although I am not sure if that is working yet.

I usually use picasa.   you just have to take their link they give you and parse out the right part.

radollar2000User is Offline
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19 Jan 2009 07:22 PM

yeah I don't think the attachments option is working, there isn't anything below the text editor portion. My post screen shows only the text editing stuff then is followed directly by the text entry window. So I guess I'll just have to wait a few.

Greg McFaddenUser is Offline
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19 Jan 2009 08:11 PM

email me the photos at EMAIL REMOVED  (parse appropriately to turn into a real email) and I will get them up for you.  I would highly recommend a picasa album as it does allow linking...

 

I got it.  will post after work...  uploads don't work from work

 

-Greg

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20 Jan 2009 08:49 AM

there ya go dude. ALL. These are the pictures he was trying to upload
radollar2000User is Offline
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20 Jan 2009 09:55 AM

Thanks Greg! So yeah, Any comments on proper rib placement would be welcome. Again there is 2" space between the 6 ribs in the bow and roughly 3.5" spacing for the rest of the ribs. The black line is the water line. At least that is as close as I could get it with the plans.

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20 Jan 2009 11:45 AM

The stringer looks way too thick (assuming that is what the tape down the middle is for).  IRC limits that to 1/8"...  I believe it is the same for MWC/Treaty...  I do not know about big gun.

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20 Jan 2009 12:57 PM

DOH!!!! Thanks for catching that. I knew that. One other question concerning the stringer. Does it go on the waterline as the plan shows or is there a maximum limit to how close it can be to the water line?

Greg McFaddenUser is Offline
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20 Jan 2009 03:31 PM

 My understanding is that it goes where it is needed when there is an armor bulge or something like a step in the shape of the hull where it would be difficult or impossible to sheet without it.    Generally, no need = no stringer.  Personally, from the pictures I see no shape warranting a stringer at all.   Hopefully others can chime in here and help.   Which format?   that way we can get to the authoriteis in that format faster...

radollar2000User is Offline
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20 Jan 2009 03:44 PM

This is going to be for fast gun. The plan shows what I'm guessing to be an armor belt, but as you said the hull doesn't show any bulge or anything along that section so I was just guessing really. Also, concerning the stern, is the entire thing left impenetrable? Another question I just thought of was what size CO2 tank I need? I figure I could get away with a 3.5 oz bottle, but I probably have the space and weight for a 7 oz.

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21 Jan 2009 12:03 PM

3.5 should be fine...  you may want to mock up the internals prior to cutting to see how everything fits and floats (or at least load it down to proper weight so it floats correctly and then see where the CG is...  so you can match it while you build).  My own preference was to build it up completely (or mostly there) prior to cutting the windows to make certain everything fits and it floats correctly...   then I can also adjust ribs if I need tieoff points at a particular location and I can float it and fuss with it without risk of breaking the sheeting...

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21 Jan 2009 02:37 PM

HMMM Yes yes I can feel the wisdom flowing into my head! That is a good idea. Thanks.

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21 Jan 2009 03:18 PM

A 3.5oz bottle will get you one sortie. Two sorties would be a stretch, you'd run out of air before bbs. You should have room for a 7oz bottle, but you might not have weight for it. As big of a ship as it is the weight is an issue.

The whole round stern is solid and the back 1" is also solid, you have to messure with the shape of the hull. Might as well space the ribs evenly, maybe a couple more up front,  you've got so much freeboard it doesn't mater that much.

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21 Jan 2009 06:37 PM

Okay thanks a bunch Bob. I'm going to be using 6 NiMH 10AH D Cells to power the boat so I'm hoping that will help mitigate the extra weight of a 7oz CO2 bottle.  Also I'm probably going to wire together 5 AA 2.7AH NiMH for the reciever and servos.

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22 Mar 2009 09:53 AM

Okay so after much time spent reworking a few things, I ve got a few more pics to add. Also it helped to see a bunch of already built boats at the recent Bayou battle. Thanks again guys for all the good advise and insights!

this view shows the internals that I've finished that aren't completly fubar.

So in this picture the foreground shows the radio box (undergoing changes as per several suggestions) and the sub deck (un-glued for ease of work). Mid-picture is the 7oz CO2 tank with the drive motor wires along either side and the spaces for the battery packs. Also shown is the concrete seleant used for the water channal (which the radio box and the CO2 tank are hiding. Just aft of the CO2 tank is the 1/2 unit Bilge pump and the drive motors. In the extreme aft is the rudder servo and servo water box. The servo rudder linkage will be changed out for a dual arm setup also per several suggestions.

Closer view of the motors and electrical connections

Overhead view of the rudder systems

My latest project is still concerned with the main drive batteries as I have meet with extream difficulty getting wire to solder onto the battery ends. So as I get systems finished I'll post more pics.

jadferUser is Offline
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22 Mar 2009 06:09 PM

What happend to the pictures? .. Nevermind they showed up finally

SMS Baden - Battle Ready FN Gloire - Battle Ready DKM Uckermark - Battle Ready A Trembling backseat shrimp - refit SMS Von Der Tann - mothballed
BobUser is Offline
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23 Mar 2009 06:25 AM
It looks like you have your motors wired in series. They should be in paralel so each one gets the same voltage. If you go in series the motors will split the 6 volts and each get around 3 volts. Way too slow for a Des Moines.
The push together connectors you are useing will work for a while but will start to corrode and cause higher amps and poor connections. Deans Altra Connectors or Power Pole connectors are the way to go.
How do you plan to keep the water tight rudder box water tight? Looks like it's more of a bath tub then a water tight box.
radollar2000User is Offline
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23 Mar 2009 09:37 AM

Okay well the motor wiring ought to be easy enough to change while I change out connectors. The rudder box is simply there to keep the water at bay until the boat sinks. I've applied skotchcote to all my servos and batteries so theoretically they can take a dunkin'.

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