4.5mm WetLink Penetrator doesn't seat properly in the end cap

I’m installing some 4.5mm WetLink penetrators (WLP-M10-4.5MM-LC-R1-RP) and I see a problem that may or may not be a problem. I must be missing or misunderstanding something. The o-ring on the bottom of the bulkhead doesn’t seat against the end cap. It is too small. When looked at from inside, you see the whole o-ring, meaning that it isn’t sitting up against the metal of the end cap at all, but sitting down inside the hole. It’s like the hole is too big or the bulkhead too small. (See photos, but it is hard to see looking through the hole from inside using my iPhone.) Is there an adapter for these smaller WetLinks? Please help!


I now see that, for the 4.5mm only, they sell M6 and M10 models! This is really frustrating! What are the M6s even for! There is no note about these being incompatible with the enclosures. Before I purchased I watched the video on installation, read the directions on installation, and read " How to Choose a WetLink Penetrator". I see now that two different 4.5 versions are listed but it isn’t clear why and there is no note about one being for end caps (like all of the other sizes) and one being for something else (god knows what). This should be big and bold. Oh, I am so frustrated. I have a deployment in three days and it is a Sunday.

Hi @rangewider,

Sorry to hear about your ordering mishap. I’ve raised this internally to see if we can expedite the shipment of your M10 replacements, but that won’t be seen until Monday. In the meantime I’d suggest you place an order for the ones you want, so the shipping address and payment don’t hold anything up, and then send an email to sales@bluerobotics.com linking them to this thread so they know who you are and which order it is. That’s also the place to bring up what can be returned/refunded of the ones you’ve already bought :slight_smile:

We currently sell three different thread sizes of WetLink penetrator (M6, M10, M14), for different cable sizes and purposes. We use the M6 ones on some of our smaller products, like the Ping Sonar and Lumen Lights.

The technical details and item names are already organised by bulkhead size, but I’ll add a note just above the ordering selection, and potentially one in the choosing a penetrator guide too :slight_smile:

This is done now.

There’s a note on the product page, and I’ve added a section for Bulkhead Sizes to the choosing guide :slight_smile:

The installation guide already mentions the different sizes in the tools section:

and the assembly section:

so I’ve left that as is, but if you can think of a way that could be extra clear there too then suggestions are welcome :slight_smile:

I appreciate the response and willingness to help expedite. I do see that, if you understand the system better than me, it is clearish on the site. But I’d recommend going a little further on the pages to make sure this doesn’t happen to anyone else who is new like me.

I’d separate the 4.5 M6 completely and make it an entirely separate item for order with its own page and options. I’d call it a thruster penetrator and the others enclosure penetrators. I’d also include a paragraph in the “choosing penetrator” page about the distinction.

I think I also have the wrong wench since I got the wrong size of everything. I’ll include the right one in my new order.

Thanks again.

The WetLink Penetrators aren’t confined to being used for our specific products, or even for only underwater uses - the whole idea is that they’re robust and water-tight, and cover a broad range of applications.

I’m not sure what you mean by “thruster” vs “enclosure” penetrators - M6 penetrators are generally used in small products (as discussed in my previous two responses), while M10 are for larger ones (and fit in our existing enclosure holes), and M14 are for larger again. It would be possible to have a custom end-cap on an enclosure that uses all three sizes, and different thruster sizes could also end up requiring different penetrators.

Splitting out different bulkhead sizes onto their own pages would likely make it unnecessarily difficult to find and select a suitable size. It may be possible to change the interface to have cable size and bulkhead sizes as ‘filter’ options that then allows choosing between any options that would fit those specifications, but that would likely be quite complex to implement. If this becomes a repeated issue then it’s something we’ll look into, but as is hopefully the existing notes and comments on the different pages should suffice :slight_smile:

That’s already done, as per my previous comment :slight_smile:

Thank you so much for the help and clarification. I’m really enjoying the system and look forward to growing my understanding of how it all goes together. I’ve certainly learned a lot through this.