Attaching Porta Bote racks to the side of my RV

[Geocritter]

I recently purchased a second-hand 12’ Porta Bote. To mount it to the drivers side of my 33’ 1994 Class A Holiday Rambler I purchased the Porta Bote mounting racks. Since my HR has an aluminum body shell on the sides and the Porta Bote weighs just over 80, lbs I’d like to attach it where there are underlying vertical support framework members. I thought at first of looking for rivets to identify the location of the vertical support members but the only rivets I’ve found are a horizontal row of rivets running down the sides of the RV, I’ve found no vertical rows. Does anyone know any non-destructive ways to find the vertical support members I’m looking for?

Steve

[Geocritter]

Mr-MrsPete wrote:
Have you thought about using your knuckle and tapping down the length of your RV and listen for the harder spots?

I've been doing that and there are some likely places, however the inside aluminum structural members aren't very wide and I'm not certain I can define where to drill/attach with the accuracy I need.

Steve

[Mr-MrsPete]

Have you thought about using your knuckle and tapping down the length of your RV and listen for the harder spots?

[YC_1]

I never thought of the thermometer. Just for fun I will give that a try.
Sometimes a stud finder will help. The humidity thing works well too. Guess I should take a picture and annotate it with measurements for future things.

[Geocritter]

fcooper wrote:
If you're not in a hurry, wait and watch the exterior of the rv on a cool morning when humidity is high. Under the right conditions, the moisture will condense on the side of the rv in a pattern that displays the underlying supports. It's not very scientific, but also non destructive.

Have you considered a rack with covers under the RV? I've seen several of these described in previous posts.

Fred

Actually it is pretty scientific and a good idea. Using that same science I might be able to locate the supports using an infrared thermometer. Thanks!
Steve

[fcooper]

If you're not in a hurry, wait and watch the exterior of the rv on a cool morning when humidity is high. Under the right conditions, the moisture will condense on the side of the rv in a pattern that displays the underlying supports. It's not very scientific, but also non destructive.

Have you considered a rack with covers under the RV? I've seen several of these described in previous posts.

Fred