Transom and jackplate bolts.

**Captaincj** · 05-18-2019, 07:22 PM

I replaced my transom to jackplate and jackplate to motor bolts last year with F593C-THE bolts.

The boat gets low hour use, freshwater, never jumping wakes (intentionally) and if the water is rough I don't go out... Hydrostream Viking.

Did I use the wrong bolts? If so, how bad?

Thanks

Christopher Johnson

**XstreamVking** · 05-19-2019, 05:48 AM

What is f593c bolt?

Tap bolts are similar to hex bolts except they are fully threaded no matter what their length. They are designed to be used in drilled and tapped holes. They are used in applications where a stud with a nut on each end would be impractical. Used in low strength applications. Stainless Steel material.
Not much info I can find. Full thread? Designed to be used in threaded holes? Not liking the used in low strength apps......I would get some fasteners from a source that can tell you what the fasteners are actually rated for. As always, jm2cts...

**Captaincj** · 05-19-2019, 07:36 AM

It's a technical specification for a higher strength stainless steel bolt as far as I can find:

https://www.portlandbolt.com/technic...ons/astm-f593/

**Captaincj** · 05-19-2019, 07:43 AM

Also, just noticed the heavy-duty bolts that hold my jackplate together (from the factory) are labeled F593C.

**savage** · 05-19-2019, 07:45 AM

I went with ARP bolts, they were expensive, but I'm not worried about any bolt failures now.

**Ron V** · 05-19-2019, 08:10 AM

F593 is an ASTM standard. The bolts with that marking meet the standard, whereas a generic 304/316 stainless bolt may not. They are the same or similar to what the outboard manufacturers put in the crate with the motor, and are plenty adequate.

**Captaincj** · 05-19-2019, 08:16 AM

Thanks Ron, I did feel better after seeing my jackplate assembled with the same bolts.

**XstreamVking** · 05-19-2019, 10:51 AM

I just googled them and that is what they came up with. The consensus is use them.....

**Captaincj** · 05-19-2019, 10:58 AM

Thanks gentlemen.

**Gorilla0178** · 05-19-2019, 11:48 AM

Originally Posted by Captaincj

Also, just noticed the heavy-duty bolts that hold my jackplate together (from the factory) are labeled F593C.

Second this. Same here. It's a standard. Now the bolts sent with are usually fine thread. Hardware store bolts are coarse thread. Make sure to grease them, coarse thread gall (galling) pretty easy.

**Captaincj** · 05-19-2019, 12:36 PM

Originally Posted by Gorilla0178

Second this. Same here. It's a standard. Now the bolts sent with are usually fine thread. Hardware store bolts are coarse thread. Make sure to grease them, coarse thread gall (galling) pretty easy.

Thanks.