Dingy Davit Install Question

midexp

Active Member
Oct 5, 2016
423
Harrison Township, Michigan Lake St.Clair
Boat Info
1999 40' Sundancer
Engines
454 merc
Just Bought Nautley davits. Looking at their installation directions, they recommend applying 3M 5200 under the mounting bracket pads the Nautley's slide into. 5200 seems kind of drastic. What have others done?

Also, I do not intend on fabricating a metal backing plate for support to the underside of the swim platform. Platform is very solid. Don't think the plate is necessary?

Also, I get applying sealant in the mounting holes I will drill into the platform. With the bolts in the holes, this will seal. But what have others done about the hole that is needed to pin the davits into the mounting brackets? Seems this hole will be drilled, but can't be sealed?

Lastly, I plan on buying ratchet straps from local home center. Any lessons learned on what to and not to do as far as tie downs? BTW, DingyRamp wanted $40 for one mounting D-loop . Several other sites have the same one for $15.

Thanks
 
I would install backing plates for sure, and 5200 doesn't seem drastic, as I used it on mine (piece of mind)
 
use 4200 if concerned - if it is visible get the uv protected version....as far as the holes, most will tell you to drill oversize, fill with epoxy and then re drill the correct size - i once added a st croix mount and it actually came with a bushing for the pin - again, drill oversize and seal the bushing in place.

as far as ratchet straps are concerned, i would get stainless - cheap ones will corrode, stick and make a mess in a marine environment.
Edit - just saw you are in freshwater - maybe the cheapies will be OK
 
Agree, DON’T use 5200. Use one of the 4200 variants or LifeCalk. 5200 is only for parts you never ever ever want to come apart. Like a hull to to deck joint. The the gelcoat / fiberglass bond will fail before the 5200/gelcoat bond.
 
I would say no on the 5200. As stated above, adhesive bond is too strong.
I would use backing plates.
Picture below shows the mounting holes and retaining pin hole on my Davit plates after they were over drilled and filled with epoxy and bolt size holes drilled through the epoxy. The retaining pin hole is ready to receive the insert that gets sealed into it. The 4200/4000uv or life calk recommended above would be good. On my swim platform, I definitely wanted something recommended for below the waterline.
The cheap big box store ratchet straps worked fine and lasted 2 years here in the Great Lakes, then we went south and they lasted about 2 weeks in salt. I now have nice stainless steel ratchets that I bought at strapworks.com
Good luck.
3ED612F9-C511-4178-BEFA-ACE3F38282DC.png
 
Thanks guys. I don't have a machine shop to cut and drill a metal backing plate, but I plan on using as large of washers under the platform as possible. Mark, where did you get the inserts for the drilled holes? I do't think they are needed for the holes the mounting bolts go thru? Just the pin.
 
The insert was provided with the Davit plates for the pin, there are no inserts for the bolts.
Holes are drilled through for the bolts, a little core material is removed from between the fiberglass skins, place some duct tape or ? under the holes to help keep epoxy in place until it sets, wet it out with unthickened epoxy, after an hour or so it will begin to set, mix up more epoxy this time adding structural filler to mayonnaise or peanut butter texture and fill the holes with it before the unthickened coat fully sets. Next day, drill the correct size bolt holes. Pin hole is the same but of course does not get drilled through. Insert goes in that.
Around our area there are suppliers for small quantity metals like Metal Supermarkets, metalsupermarkets.com they will shear 1/8 or 3/16” stainless sheet into backing plates of the size you specify. Maybe you could find something like that around you.

Is this all extra work. Yes, but the davit guys want to make it sound like easy peazy install so they can sell Davits.
There is a saying that goes “ There’s the right way, the wrong way, and the way somebody has gotten away with”. In my opinion the instructions that came with my davits saying just use 5200 is what you probably/maybe? can get away with.
 

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