Replacing outboard mount on CD26

[jwilkerson]

I'm looking to replace this old corroded outboard mount on my CD26 and I'm wondering what materials I should use. Is 316 stainless steel the best for the fasteners and brackets? Would a metal fabricator be able to reproduce the old brackets so that I can avoid drilling new holes? Is marine plywood a good material to use for the backing plates? Starboard? I think the old ones are wood but it's hard to tell. Thanks!

Outboard well with mount

PXL_20230716_203340519.jpg (2.91 MiB) Viewed 367 times

Close up of the old bracket

PXL_20230716_203345898.jpg (2.28 MiB) Viewed 367 times

Backing plate

Outboard well with old mount

IMG_20230727_152532.jpg (2.11 MiB) Viewed 367 times

[Jim Walsh]

This would be my choice for the “L” brackets

https://www.mcmaster.com/products/metal ... 90-angles/

This would be my choice for backing plates. Plywood is not suitable though it can last for years if the end grain is saturated with thinned epoxy and all surfaces are epoxy coated.

https://www.mcmaster.com/products/plast ... nd-strips/

For the actual motor mount my choice would be a piece of clear Douglas Fir…used to be widely available in any lumberyard. Not my stomping ground so I presume it is still commonly available.

Stainless fastenings are fine. Bring a magnet…they are mildly magnetic at times but should not be strongly attracted if quality raw materials were used.

[Frenchy]

There's a few good ways to tackle this job, I think. Jim's is a good one. I think I might go for fiberglass
angle- 1/4" or 3/8" thick. For the backing plates- if the originals are not rotten, you could just reuse them.
If they are, I would go for 1/4" fiberglass plate. The mounting board could be douglas fir or white oak or
perhaps three 1/2" fiberglass plates epoxied together to make a 1-1/2" thick board. The white oak is resistant to rot.
The fiberglass plates and angles are also available from McMaster-Carr.



https://www.mcmaster.com/products/angle ... angle+bars

[jwilkerson]

Thanks both for the replies.

Is galvanic corrosion a problem when using marine aluminum angle brackets with stainless fasteners?

Using fiberglass for the angle brackets is an interesting idea. Are there any drawbacks to using that over metal?

There's a lumberyard nearby where I should be able to find douglas fir or different hardwoods.

[Jim Walsh]

You could always slather on some Tefgel but for all practical purposes, there will be no real issues for decades, it’s fine. You could always use bronze brackets and hardware but most would balk at the expense. Stainless brackets and hardware would be less optimal than bronze at less cost.