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Thread: Aquarama

  1. #76
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    If you can paint models I can probably have a go printing something using my 3d printer.

    PM me for examples.

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  3. #77
    Join Date
    Dec 2011
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    Harrington, NSW
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    Next job on the list is to fit the cold water pick up tubes.

    I had to relieve the holes I drilled in the hull previously as they were full of 2 pak from the painting of the bottom.

    205.jpg

    Using a small round file to ease out the holes to 6mm.

    207.jpg

    Preparing some 6mm copper tube for the pick ups. Cut off at 60 deg.

    208.jpg

    Trial fit the tubes

    211.jpg

    the tubes were temporarily held in place with good ol Bluetak so I could turn the boat over and epoxy the tubes into the prop tube logs.

    212.jpg

    Slow epoxy used to flood around the pick up tunes. Trial fit some water tubing - clear 5mm vinyl from Bunnys.

    215.jpg

    All done now, to run the cooling pipes, it's going to be a bird's nest of tubing. I have to go from the pickup to the ESC to the ESC second ESC cooler, to the water jacket on the motor and then back to the exhaust tuning already fitted. Twice!

    216.jpg

    Stay safe kids! ..... 2m .....

  4. #78
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    Dec 2011
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    Harrington, NSW
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    Re previous post photos.

    Prop Tube grease problem
    Prop tube grease?
    After I installed the prop tubes and props I used a syringe to inject grease into the empty tubes. Then I installed shafts and props.
    When I run the motors for a test a lot of grease was being flung out from the motor end and from the prop end making quite a mess.

    There are no seals as such against either end bearings but the prop end has a nylon washer between the bearing and the prop.

    The grease I used was "Herschell" White Marine and Outdoor Grease.

    Is there anything I can do to stop this happening?

  5. #79
    Join Date
    Jul 2011
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    Default Grease

    On a real boat, there’s a seal on the inboard end of the propeller tube (the shaft log it’s called) and it keeps the water out, and the water that comes up to the seal lubricates the skeg bearing. If the engines are rubber mounted, as they are in big boats, there must be a gap between the front end of the propeller and the skeg hanger as the torque when the engines are working and the boat is running will cause the shafts to push forward and therefore the propellers move up towards the fixed skeg hanger. In your case there’s probably not enough force for this to be a problem.
    The other way I’ve seen is the shaft tubes (or logs) are long enough to be above the waterline of the hull, therefore stopping water coming inside, with a simple shroud seal on the shaft to stop any splashing during reversing, the small amount that comes in gets pumped back out with the bilge pump eventually.

  6. #80
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    Jan 2014
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    Default

    You could cut a reverse thread on the prop shaft itself to form a scroll seal.

  7. #81
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    Dec 2011
    Location
    Harrington, NSW
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    I can't cut a thread here. The shafts run in opposite directions any way as there is a right and left hand prop and the shafts counter rotate to stop the back of the boat from walking sideways.

    Maybe this?

    OXID eShop 4 | Shaft Sealing Ring 4-11-6 for shaft 4mm | purchase online

    Or this? I Google translated it from German.

    Google Translate









    Shaft seal

    Classic shaft seal made of NBR rubber with stainless steel spring
    Dimensions: inside - outside - wide
    stainless steel spring









    If the last seal there could grip the inner shaft where it exits below the water line and the outer lip ran free of the outer tube and faced back towards the motors maybe it could catch the flinging grease? I suppose I would still have some oozing out from behind that flange but it may be easier to deal with.

    I wrapped some black sponge around the motor or top ends of the tubes which is held in place with a rubber band and that seems to work but would not below - pretty ghetto hey?

  8. #82
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    Dec 2011
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    Harrington, NSW
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    Seals

    I purchased some shaft seals from the prop tube supplier - China probably take forever to get here now, they are the smallest ones here. Really, they are just 4mm ID grommets but I can't get them that size anywhere else. I hope to get some sort of a sleeve that can go over the end of the prop tube to house the seal. 9.5mm tube? Will try to compress the seal in there with the prop mount sleeve.

  9. #83
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    Quote Originally Posted by duke12 View Post
    Seals

    I purchased some shaft seals from the prop tube supplier - China probably take forever to get here now, they are the smallest ones here. Really, they are just 4mm ID grommets but I can't get them that size anywhere else. I hope to get some sort of a sleeve that can go over the end of the prop tube to house the seal. 9.5mm tube? Will try to compress the seal in there with the prop mount sleeve.
    I know it sounds obvious, but what about some heat shrink tubing? Wrap a thin tape around the log tube, and shrink it down onto the shaft and the log, then remove the thin tape to give clearance. If you can get it on from the inboard end it would work ok.

  10. #84
    Join Date
    Dec 2011
    Location
    Harrington, NSW
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    I get what you are saying with the heat shrink and I have a heap of it to hand being an ex comms officer.

    I have a problem though, if you look at this picture there is a metal support leg almost on the end of the prop tubes and I don't know if there is enough outer left to grip onto. The support brackets? are fixed so I am unable to get between the prop tube outer and the leg without destroying them.

    Also will the shrink tube be able to conform to 4mm and to 10mm? I am not sure it's range is wide enough.

    Being new to this boat caper is teaching me a lot. I would have been able to foresee this problem with experience.

    I understand that real boats, ships etc have glands and such up the top to stop water but that does not seems to be used on small RC boats except for top end hydros. Most use marine grease injected into the tubes.

    Googling around - this grease flying out of the tubes seems to be a common problem with most RC guys just living with the issue. It may be that when the boat is under way the expelled grease may be washed off immediately and not be a problem. The grease may also run out and stop flinging from the lower end and still have enough grease further up the tube to be a water block anyway, I guess a shake down run will see.

    Anyway when I get the seals (grommets) I will post how I go with them.

    216.jpg

  11. #85
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    May 2019
    Location
    Brisbane
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    As a kid I built a lot of RC boats and never had special glands on the prop tubes and shafts. I remember I had only a small grease port inside the boat at the upper end of the tube and every time I put the boat to the water I squeezes some grease in with a small syringe.

    Never had any problems. The gap between the prop shaft and the tube filled with grease was seal enough.

    As you said the RC people just live with it.
    Just put it in the water do a round or two and check.

    By the way I love how your boat is coming along. Looks great.

    Sent from my SM-G950F using Tapatalk

  12. #86
    Join Date
    Dec 2011
    Location
    Harrington, NSW
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    I will run it for a while and see how it goes as you suggest, if I ever get it finished.

    Progress. Brass half round (finally found some) fitted for rubbing strips.
    Center punched at 30mm. Simple jig to hold the strips for drilling 1mm holes.

    218.jpg

    Forming to accommodate the fair curve of the top edges. I found the metal easier to form if I pulled it tightly through my fist till it was quite warm. Pinned it to shape on some scrap.

    220.jpg

    Taped in place and set in epoxy, left for 24hrs.

    236.jpg

    238.jpg

    Brass pins driven through holes, probably more decorative than used for sheer holding power.
    Screwed with SS screws on original boat. Too much for me to get SS 1mm screws.

    Acceptable for a model but I had better not run into too much with them.

    230.jpg

    3 rubbing strips fitted. The 2 sides and a long one around the spray rails and across the transom - took some forming to get it to sit nice.

    Cutwater next.

  13. #87
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    Loverly

  14. #88
    Join Date
    Dec 2011
    Location
    Harrington, NSW
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    Finally around to the Stainless Steel cutwater!

    Lots of goes at this one. The little ones in the middle are from a kit I got from Italy and are basically useless they are for an Amati Kit which is not the same as my model. I tried to get them to conform to the bow but could not make them work.

    Following suggestions from this forum and looking at "Cutwater.com" I decided to make a cardboard template directly off the bow by tracing from one side and then "mirroring" it.

    The cardboard template sat very well against the wood so I went with that.

    I went to a local boat fittings and manufacturing factory nearby and asked them about thin sheet 1.5mm SS to make the cutwater from. They had the stuff and we got into a conversation about the project. He said he would have a go at Laser cutting the cutwater if I could provide him with CAD drawings. He said it would be experimental for him to work on such a small area but he said he would give it a go and not charge me if it did not work.

    I scanned the cardboard template into the SolidWorks and produced a scale drawing for him to work with.

    The factory produced 3 items for me to try out. He said the 1mm holes were very difficult as he laser was blowing them out. Not perfect but will do. If I did it again I would try "Hydro cutting" but the nearest one is hours away.

    Cost? 20 bucks - cheap.

    239.5.jpg

    I found it impossible to weld the center seam up. Tried standard solder and Silver Solder but it would not stick. The guy said he doubted that I could due to the high content of chromium in the marine grade sheet metal. So I formed it onto the hull as best as I could. Maybe someone handy with tiny brazing could have done it?

    Anyway I resined it in place and when set drove brass brads in for effect and some strength. I filled the small gaps in the seam with filled tinted with grindings of the SS sheet.


    239.jpg

    Given this started out as a wooden model it has moved on a fair way.
    Looks ok but I will try not to run it up the bank too much )


    240.jpg

    Almost finished. Fooling around with the radio gear. Another challenge.

  15. #89
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    It looks a good job but I do think it’s detracting from the timber boat tradition. I can’t remember ever seeing one except on barges that work logs around sawmills on American lakes. But, for a first timer, you’ve done a mighty good job, be proud of yourself.

  16. #90
    Join Date
    Dec 2011
    Location
    Harrington, NSW
    Posts
    119

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    Thanks very much. I put it there for authenticity. Seems like they were common on Aquaramas from that vintage.

    This is a stock photo of an original. Got a spare 2 million $$ ?

    Lights to come next!

    Bow Beauty.jpg

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