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I couldn't tie it to the mast as I don't even have the mast on the boat at the moment. We are off on a river cruise in a few weeks and the mast is staying at home.

I'm confident the Seahouse outboard support bracket will work well and it didn't take bugger all to put together (Translation to English: was quick and simple to make ).

Well, since I can't just leave something alone until I know more about it, I took a couple of force and dimension measurements on my BF50, determined where the CG is of the tilting part (up/down and fore/aft), and calculated the forces on the hydraulics in the up and down position, and under load when motoring at full speed.

In the up position, where I keep it when trailering, the force on the lift cylinder is about 150 lb. Which sounds about right, given the geometry, and the fact that I can unload it to where the lash in the pin is with about 15 lb force at the fin under the prop.

In the down position, but just off the lower stops, the force is about 450 lb, which also sounds about right given the 70 lb of horizontal force it took at the bottom to unload the pin again.

In the down position, and putting 2/3 of the shaft hp into thrust at 16 mph (my top speed), which is 780 lb, puts an additional 5100 lb of force on that cylinder, for a total of 5555 lb of cylinder force.

That's all static force, and of course, dynamics will increase it, especially when motoring hard with the OB trimmed off the stop.

But bouncing down the road on the back of the boat, a load factor of 2 only puts 300 lb on that cylinder, which is capable of at least 6000 lb (probably more), so I'm not worried about it. Hydraulics just aren't that delicate.

I'll continue to keep the tilt lock down, in case of a failure of some kind, but it's never drifted down to where it's made contact, even on a long ride, and if it did, the lock will stop it. It's relatively robust. Others may not be, but the Honda's is.

I am sorry but masts are not designed to take lateral forces they are designed to take compression forces. Putting a side load on the mast with a lever (the bit hanging out past the mast crunch) is just not a good idea. Why risk a part of your boat worth big $$$$ when you can fabricate a part out of scrap for a few cents?

And as Tom says I have not used anything for years without problem it is more a backup in case of a hydraulic leak on a long trip.

Gezz I'm sure you engineering types pull numbers from your hats half the time No doubt you are about right and it may never be needed, but a bit of back up on the hydraulics gives me a bit of peace of mind and only cost me $4 in bolts and an hour in my shed drinking beer and messin about with boat stuff. I think they sell something similar in the chandlers here but they are designed to latch onto the end of powerboat trailers and are no use with a sailboat trailer.