1 have a 93 20 ft fun deck, need to replace the swim ladder but I can't remove the existing screws,

dhardesty

the screws just spin but will not come out

dward0

sawzall off the heads and fill the holes?

cjjjdeck

Many components are installed in the hull and deck sections before the two are mated during the construction process.  The problem is those components are sometimes not reachable after the boat is finally assembled.

If you don't have access to the nuts underneath the ladder area, then you won't have much choice but to proceed as dward0 suggests (you could probably drill off the heads too).  You should probably use a moly type hardware system when you go to replace the ladder assembly like a stainless steel Snap Toggle (just make sure the bolt size matches the mounting holes on the ladder assembly).  This way it will be much easier if you ever have to service or replace it in the future.  I would also recommend using anti-seize compound on the bolts.

Here's a link to the Snap Toggle website:
http://www.toggler.com/products/snaptoggle/overview.php

nquirk

One other option I've seen done is to cut an opening to access the underside and replace the cut out area (3-4" open with an access port)  Example, if its the aft ladder, some boats with a bilge area (outboard models) you can cut an open on the side of the bilge area to access the underside and add an additional access port for future use.  If you do this however, make sure you plan it well as the access port needs to fit the open (read:  don't make the hole too big) nor near the top.  

Each boat is unique so you'd have to determine if its possible.  And don't consider the deck area, as the traffic from the ladder, these access ports aren't truly designed for high traffic.

Something to consider if you comfortable doing so.

englishchicken

A sawzall is tough to fit in there.  I'd recommend a grinder.  It made fast work of it.

dhardesty

thanks for the help, drilled out the holes and used a heavy duty rivet gun to install the new ladder.

cjjjdeck

Appreciate the update!

I've not heard of using rivets to attach a ladder before, maybe post a picture and let us know how it holds up!

M99

Rivets:  Just curious.  How did you gain access in order to buck those rivets if there was no access for the original nuts, and what did you buck them against if it is fiberglass?  If you used Pull Rivets, that would not be a very durable fastener for a ladder. For any type of rivets, you would need a metal doubler plate at the bottom.  They won't hold tightly for long against fiberglass or wood.