The blue bolt on cap slipped out of my hand and dropped way back under engines. The space is tight with engines and a generator to access. I gave up. The cap felt aluminum so maybe not going to be pulled by a magnet. I don't see any caps that are available to order online. The phone at Latham rings but no answer. Anyone else have suggestions. Can I run without the cap? Thanks.

Try a wire coat hanger untwisted with a gorilla tape ball/loop on the end and fish it out. May take a couple of tries. Don’t give up.

If the above don’t work, use a shop vac. I taped a stick to a mini shop vac hose to get some washers.
Call Latham if you still can’t get it.

I tried can get the bent hanger and got pretty far back. With a mirror I see a stringer running laterally which stops me from getting much further. I don't see the blue cap anywhere. I'll call them tomorrow. Maybe order 2 or get the size and go to the hardware store for the same size bolt. If not possible the wetvac next.Thank you both!!

you could try using a hose and flushing it forwards, then one of those grabber sticks. maybe the bilge gods will be kind.

Are you sure it dropped all the way down?? Sometimes that crap finds a tiny little place to get hung up on. Get a good LED white flashlight, shine it down the sides and back. You will probably see it.

Latham is mailing me a new cap with 2 day shipping but I will try again to get the original one. They seemed very helpful on the phone so hopefully coming before the weekend.
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To prevent this from happening in the future, drill into cap at one of the corners and attach some safety wire to it. If it falls, it will only go so far.

Also, take a bright LED and look for it at night. Much easier to see.