How do i stop water entering stuffing box ?

[Andris Golts]

Hi all this past weekend i was doing more set-up work on my 24'' 1963 version of the Miss Triftway i raised the strut by 1/4'' and greatly improved hull speed and handling after a 2 minute run there was a good 1 1/2 oz's of water in the hull i pressure tested the water cooling system no leaks. Checked the hull for cracks none to be found. Removed the flex shaft from the brass liner and re-greased the flex shaft with Mercury 2-4-C grease and ran the boat for 1 minute water in the hull sprayed up inside the cowl where flex shaft exits brass liner. Any suggestions how i may be able to stop water entering between flex cable and brass liner ? Never had this problem with any other boat ? Regards Andris Golts.

[dmitry100]

you can try using a bit of heat shrink or tubing to "seal" the space between flex and tube

[rol243]

add some heat shrink on the strut end as well.

[martin]

Yep put a piece of silicon water tube on the motor end of the stuffing tube, make sure that the silicon tube I/d just barely closes onto the flex otherwise the excess friction will cause heat. As said also seal the stuffing tube to the strut as well with heat shrink or silicon sealer.

[Andris Golts]

Thanks to all for the great information i always put heat shrink tubing between the strut and stuffing tube. Now i will have to come up with either fuel line or heat shrink tubing at the other end thanks again . Regards Andris Golts.

[785boats]

Beveling the front edge of the drive dog can also stop water being forced up the stuffing tube too.
The bottom one is bevelled & the top one is not.

Also a pic of a shaft with some tubing over the stuffing tube & onto the shaft.

[MarkF]

Since you have to have a gap between the drive dog and strut, how does bevelling the drive dog do anything?

Mark

[martin]

The way I understand how the front bevel on the dog works is when theirs is no bevel water is constantly trapped in the gap between the strut & dog face. The water flowing past the strut assembly is at a different pressure to the trapped water in the gap, this difference in pressures forces the trapped water in past the shaft & bearing & up into the stuffing tube & into the boat. Having the bevel helps stop water getting trapped in the gap.

[Andris Golts]

Thanks 785 boats i will chuck the stub shaft it in the lathe and put a bevel on the front of the drive dog. Regards Andris Golts.

[rol243]

Its also abit like a bullet flying through the air, which bullet will have less drag ? a flat blunt one or a pointed sharper one ? so having the tapper on the drive dogs front face does definetly help any water getting away as opposed to being caught and sucked into the shaft tube.

[ray schrauwen]

Is it aquacraft that made beveled drive dogs or Proboat?

[martin]

Is it aquacraft that made beveled drive dogs or Proboat?

Aquacraft certainly still use them.

[785boats]

Since you have to have a gap between the drive dog and strut, how does bevelling the drive dog do anything?

Mark

Mark.

The way it was explained to me, many years ago, was that the water hitting the face of a drive dog is deflected forward as a sort of a shock wave & is forced up past the bushings. Slightly worn bushings can suffer more, while sealed bearings that some people use won't suffer at all. Beveling the face of the drive dog deflects the water away from the shaft.

Andris.
I don't have a lathe, so I simply put them on the end of a piece of 3/16" steel rod & spin it in a drill while holding a file to it to create the bevel.

[MarkF]

Does it matter when we run a teflon washer thats usually same diameter as the strut? Since most of us run a washer between the strut and drive dog it seems like water will hit the washer before the drive dog. I guess you can leave the washer off.

Mark

[martin]

I never run Teflon washers as when using a 1 piece flex & stub shaft with the appropriate gap ie the diameter of the flex im using, 3/16" flex = 3/16" gap at the strut to dog. With the correct gap the dog should never come into contact with a Teflon washer anyway.