Nut On Curved Surface - Moderated Discussion Areas

  ContinuousWave
  Whaler
  Moderated Discussion Areas
  ContinuousWave: Whaler Repairs/Mods
  Nut On Curved Surface

search | FAQ | profile | register | author help

Author Topic:   Nut On Curved Surface

picflight posted 06-27-2014 04:46 PM ET (US)
I am reinstalling the trolling motor bracket mounted via thru-hull 3/8" bolts on the starboard side transom of a 1998 Outrage 17, same way it was installed originally. The motor that will eventually go on will probably weigh about 90-lbs.
The lock-nuts seemed to be originally hand torqued on the curved corners of starboard side storage box. This is my guess based on the effort it took to loosen the bolt and nut.
There are no cracks, so it looks like the installation and torque worked for 15+ years.
What options do I have to tighten on a curved surface?
Do I fabricate washers that are flat on one side and following the contour of other side?
Or can I use the new SS 316 washers as shown in pictures below?[/b]

This is what it looked before.
https://www.flickr.com/photos/picflight/14520642552
Original bolts
https://www.flickr.com/photos/picflight/14498614526
Outside
https://www.flickr.com/photos/picflight/14520651812
Inside
https://www.flickr.com/photos/picflight/14521709515
contender posted 06-27-2014 09:18 PM ET (US)
I would get a small section of brass or bronze pipe or a bushing that can be fit over the bolt and cut at the angle and use it for a level spacer, the angle will mate with the curve and then the flat side you can put a nut on. If you can not find the above another idea would be a peice of KING StarBoard 1.25-inch thic. You could cut the angle to fit. Good luck
picflight posted 06-28-2014 12:27 AM ET (US)
Thanks for the ideas contender.
jimh posted 06-28-2014 03:19 AM ET (US)
Use a piece of hardwood. Spread the loading over a surface ares of a couple inches on the rounded transom side. Shape the wood to fit the curve. Then drill a hole in the wood so the fastener head or the nut will sit flat on the flat surface of the wood spacer.
Binkster posted 06-28-2014 08:00 AM ET (US)
I like contender's idea, it's simple and permanent. Shaping hardwood to fit a curve is not easy to do, will need maintenance, and is not professional.
rich
jimh posted 06-29-2014 09:15 AM ET (US)
Shaping wood is easer than shaping metal.
Wood is used for strength inside the transom, so there is no reason to associate using wood outside the transom as being somehow inferior or non-professional.
Wood is easily preserved with top coatings like epoxy and varnish.
In the curved area of the transom where these mounting bolts are being installed, it is unlikely that there is wood immediately below the curved surface of the gelcoat. I very much doubt that curved wood was used as a reinforcement inside that part of the hull. By using an exterior piece of curved wood, you will spread the loading over a larger area and avoid indentation of the hull laminate.
contender posted 06-29-2014 03:07 PM ET (US)
The wood will crack the others will not...
jimh posted 06-29-2014 03:51 PM ET (US)
What about the wood embedded in the transom that provides the fundamental strength of the transom structure? Are you recommending it be replaced with brass or bronze, too?
contender posted 06-29-2014 04:03 PM ET (US)
The wood in the transom is compress and covered in fiberglass, And the correct way to drill the holes in the transom would be to make a sleeve that the bolt goes through and does not touch the wood in the transom, Then the sleeve is sealed in fiberglass, but no one does this because its to much work. The wood in the transom is for strength, just like steel in a building, then the steel gets covered with concrete or a protective spray. The wood in/on the bolt will be subject to water, sun, shrinking, and expanding, and after a while it will crack...PS next time you go to the hardware store tell them you wish to purchase some wooden washers...
tedious posted 06-30-2014 11:30 AM ET (US)
Depending on the torque needed, either starboard or wood might be good. Some other plastics such as G10 or UHMW polyethylene would also be and excellent, permanent solution.
Tim
jimh posted 06-30-2014 11:54 PM ET (US)
Jerry K's OUTRAGE 22 has an auxiliary engine mounted on the curved part of the transom. Jerry is a great wood worker. He made the curved inboard side spacers--that's where I got the idea. They look great, and work great. By the way, they are also coated with a layer of sealing epoxy or varnish, and they are in compression.
picflight posted 07-01-2014 03:42 PM ET (US)
Jim,
Are there any pictures of Jerry's aux motor mount spacers?

Hop to:

Contact Us | RETURN to ContinuousWave Top Page

Powered by: Ultimate Bulletin Board, Freeware Version 2000
Purchase our Licensed Version- which adds many more features!
© Infopop Corporation (formerly Madrona Park, Inc.), 1998 - 2000.

Author	Topic: Nut On Curved Surface
picflight	posted 06-27-2014 04:46 PM ET (US) I am reinstalling the trolling motor bracket mounted via thru-hull 3/8" bolts on the starboard side transom of a 1998 Outrage 17, same way it was installed originally. The motor that will eventually go on will probably weigh about 90-lbs. The lock-nuts seemed to be originally hand torqued on the curved corners of starboard side storage box. This is my guess based on the effort it took to loosen the bolt and nut. There are no cracks, so it looks like the installation and torque worked for 15+ years. What options do I have to tighten on a curved surface? Do I fabricate washers that are flat on one side and following the contour of other side? Or can I use the new SS 316 washers as shown in pictures below?[/b] This is what it looked before. https://www.flickr.com/photos/picflight/14520642552 Original bolts https://www.flickr.com/photos/picflight/14498614526 Outside https://www.flickr.com/photos/picflight/14520651812 Inside https://www.flickr.com/photos/picflight/14521709515
contender	posted 06-27-2014 09:18 PM ET (US) I would get a small section of brass or bronze pipe or a bushing that can be fit over the bolt and cut at the angle and use it for a level spacer, the angle will mate with the curve and then the flat side you can put a nut on. If you can not find the above another idea would be a peice of KING StarBoard 1.25-inch thic. You could cut the angle to fit. Good luck
picflight	posted 06-28-2014 12:27 AM ET (US) Thanks for the ideas contender.
jimh	posted 06-28-2014 03:19 AM ET (US) Use a piece of hardwood. Spread the loading over a surface ares of a couple inches on the rounded transom side. Shape the wood to fit the curve. Then drill a hole in the wood so the fastener head or the nut will sit flat on the flat surface of the wood spacer.
Binkster	posted 06-28-2014 08:00 AM ET (US) I like contender's idea, it's simple and permanent. Shaping hardwood to fit a curve is not easy to do, will need maintenance, and is not professional. rich
jimh	posted 06-29-2014 09:15 AM ET (US) Shaping wood is easer than shaping metal. Wood is used for strength inside the transom, so there is no reason to associate using wood outside the transom as being somehow inferior or non-professional. Wood is easily preserved with top coatings like epoxy and varnish. In the curved area of the transom where these mounting bolts are being installed, it is unlikely that there is wood immediately below the curved surface of the gelcoat. I very much doubt that curved wood was used as a reinforcement inside that part of the hull. By using an exterior piece of curved wood, you will spread the loading over a larger area and avoid indentation of the hull laminate.
contender	posted 06-29-2014 03:07 PM ET (US) The wood will crack the others will not...
jimh	posted 06-29-2014 03:51 PM ET (US) What about the wood embedded in the transom that provides the fundamental strength of the transom structure? Are you recommending it be replaced with brass or bronze, too?
contender	posted 06-29-2014 04:03 PM ET (US) The wood in the transom is compress and covered in fiberglass, And the correct way to drill the holes in the transom would be to make a sleeve that the bolt goes through and does not touch the wood in the transom, Then the sleeve is sealed in fiberglass, but no one does this because its to much work. The wood in the transom is for strength, just like steel in a building, then the steel gets covered with concrete or a protective spray. The wood in/on the bolt will be subject to water, sun, shrinking, and expanding, and after a while it will crack...PS next time you go to the hardware store tell them you wish to purchase some wooden washers...
tedious	posted 06-30-2014 11:30 AM ET (US) Depending on the torque needed, either starboard or wood might be good. Some other plastics such as G10 or UHMW polyethylene would also be and excellent, permanent solution. Tim
jimh	posted 06-30-2014 11:54 PM ET (US) Jerry K's OUTRAGE 22 has an auxiliary engine mounted on the curved part of the transom. Jerry is a great wood worker. He made the curved inboard side spacers--that's where I got the idea. They look great, and work great. By the way, they are also coated with a layer of sealing epoxy or varnish, and they are in compression.
picflight	posted 07-01-2014 03:42 PM ET (US) Jim, Are there any pictures of Jerry's aux motor mount spacers?