Hi Perry, you have no profile picture on your Facebook account. There are filters on this group account that will automatically decline posts from accounts with no picture to deter spam. You may want to add a picture to stop your posts being automatically blocked. Otherwise you will need to wait for an admin to login and see your rejected posts and release them. Doesn’t have to be your picture. Could be one of your boat. 😊

I don’t have a NASA system but I do have a Vexilar fish finder and depth gauge transducer bonded to the hull in my Seaforth which would be more than 19mm. It works on a iPhone/iPad app. It also links into the Navionics charts and updates depth contours. It reads depth as good as the through the hull forward facing sonar.

I wasn’t aware of that thickness limit advice when I installed mine 10 years ago and it’s been fine. Perhaps the hull where I fixed it, towards the front of the hull between the keels, wasn’t that thick but it could be.

Is the boat out of the water? If it is you can set it up inside the hull and see what the depth say then measure from the outside

‘Cygnet’ is a 1980 Macwester Mk3 she certainly has a thick hull. The NASA transducer in a tube set slightly to the Port side just forward of the engine. No problem at all.

Mine's fitted between the forward ends of the keels on a Mac Wight. I works very well.

My ‘69 Mac 26 is 16 mm thick between the keels. I found out whilst repairing a screwhole. The previous over used a wood screw to hold the bilge pump in place. In fairness to him, he did tell me I’d need to sort it. Having forgotten, I was reminded when it gouged my hand whilst rubbing down prior to anti fouling.

Money available for the trailer for the macwester 26 bilge keel

There are various pieces of equipment you can use for mast ascending. You could start with an article in yachting monthly below. I personally use a Top Climber rig with a safety line to a second halyard. www.yachtingmonthly.com/gear/climbing-a-mast-best-climbing-gear-practical-guide-83875

The mast will hold your weight! Provided you trust your ropes (not aged etc). There are a range o& techniques. Most people use a ‘bosuns chair or a foot loop. You can ask a trusted friend to ‘belay’ from the deck, possibly using a winch to hoist you as they belay. You can climb using an ascender, or a Prussia loop (or two). Just be aware that although rocks and climbing walls are ‘fixed’, masts ‘sway’ with the movement of the hull. This can be disconcerting to people used to rock!