WM has several sizes. I bought one for a grab bar for the passenger seat from them. The ones I used on the outside brow I think came from C-Dory and are the same as the handholds at the outside rear of the cabin.
If you search around, you can find some stainless steel tubing ones that match the roof rails in both size and design. However, the 3/4" stainless tube is very slick, and somewhat hard to hold onto, especially with your entire weight, if you slip.
Somewhat larger diameter teak ones provide a better handhold because they fit your hand better, so may be a better bet. safety-wise.
Then too, some plastic models with finger bumps and depressions and with internal steel reinforcement really fit most people's hands even more securely than the teak ones. See photo below, though the finger fitting feature doesn't show, unfortunately.
The plastic is some kind of elastomer with almost sticky feel, no less.
Can't give you a supplier at this date, but they're fairly common. Probably designed for a runabout interior. They come in several colors: white, beige, grey, and black.
I've got some 3/4 " tubular stainless ones for the brow which I'll probably use unless I buy teak ones to match my long rails, but these would be much more sure-handed.
One could probably use something automotive (like from the interior), except for the UV exposure over time (?).
I found a pair of nice stainless ones on the shelf at Fisheries Supply in Seattle. I mounted them on the eyebrow. They nicely fill the gap between the handholds on the cabin roof and the bow rail. I'm glad for them every time I go forward on the deck. A very good addition.
Since the canvas cabin extension cut off access to the vertical grab rails, one of the previous owners added two "truck handles" to assist on boarding. . They serve the purpose well but just don't look good. Suffice it to say that Dotty and I both need something to hold on to. I'm going to take Sam up on his offer of two 9" stainless rails. So, thanks again everybody for your help.
On a trip to Lk Powell the stainless handles on the roof became too hot to grip firmly. I went with plastic grab handles for the cover over the windows which provides security for step from the roof handles to the bow pulpit. Makes us rush across the side to get to the cool handles. Got them from Fisheries supply.
Are you installing them in the same place as the ones in the picture? What about wrapping them with a smaller diameter braided nylon line, (like 1/8 inch or so)? Gives good grip, non-slip, with a slightly larger diameter.:idea: