Trident 250 Hose sizing question

[FlyingScot]

I am installing new SD25 and 3YM30AE saildrives and engines.

Regarding the raw water intake what is the best choice?

Saildrive connection for raw water is approximately 18mm. SW pump inlet is approximately 20mm. I'll be connecting a strainer in between. Would you buy 7/8" (22mm ish) hose and attempt to clamp it down, or buy 5/8" (19mm ish) and hope to slip it over the larger connections?

I've not worked with this particular hose before.

Why doesn't Yanmar use the same size for both, I can't even begin to think of the answer.

[Jammer]

5/8" is 16mm.

3/4" is 19mm and that's what you want. It will stretch over 20mm and can be clamped down to 18mm.


Trident 250 may be overspecified for this application. Trident 130, 132, or 134 should be sufficient MIO.

[FlyingScot]

Originally Posted by Jammer

5/8" is 16mm.


3/4" is 19mm and that's what you want. It will stretch over 20mm and can be clamped down to 18mm.

Yes, meant to say 3/4" not 5/8".

Thanks for the feedback.

[Rumrace]

You could add a step down at the strainer. Use the correct size although hoses are oversized a mm the wrinkle will cause issues and stretching over puts extra pressure on the hose clamp joint and could cut the hose lamination.
I have the data to adapt one size hose to another. Like 80mm to 3” or 80mmto 90mm. If you want the data to take to a local printer no worries. We have an automotive farm industrial shop called Princess Auto. They have a huge range of hose adapters on line. Might have your size.