stainless or bronze bolts to attach struts?

yorklyn · Post by **yorklyn** » Sun Feb 19, 2012 12:09 pm

When I removed my struts one was attached with stainless bolts the other with bronze. I want to reinstall with new hardware. I believe Bronze carriage bolts would be the correct choice but im not possitive??

alexander38 · Post by **alexander38** » Sun Feb 19, 2012 12:25 pm

I'd go with bronze.

Paul · Post by **Paul** » Sun Feb 19, 2012 1:02 pm

Your choice should be based on the weakest link theory. During an impact with a submerged object, what do you want to give. Bronze bolts would give before stainless would but stainless may rip the bottom of your boat out.

When I installed the new strut in my boat, I cut the backing wood out of the hull and replaced it with hardwood covering a bit larger area and glassed it all in with heavy roving and West System. This makes the hull very tough in this area. I then cut a piece of 3/8" 304 stainless plate to use as a backer. Now the new strut is bolted thru the reinforced hull and the SS backing plate with SS carriage bolts. My thinking on this is that during an underwater impact, the strut (weakest link) would fold up under the boat with less risk of leaving a hole(s) for water to rush in.

The next weak link under the hull during an impact is the rudder. I believe Paul (prowlersfish) has a little experience with this.

alexander38 · Post by **alexander38** » Sun Feb 19, 2012 1:38 pm

also using that thought you could take the flex out of the glass and end up with a bigger hole, Bronze was use when new, so I'd stick with it. But like all thing we have a choice..

RWS · Post by **RWS** » Sun Feb 19, 2012 2:48 pm

what about dissimilar metals in saltwater?

pehaps not an issue as the shaft is stainless and the props are bronze/nibral?

should this be a consideration?

RWS

jefflaw35 · Post by **jefflaw35** » Sun Feb 19, 2012 2:53 pm

stupid ?? since i have not got this far yet, can you tell me what the struts are. or maybe show me a picture, thanks

Big D · Post by **Big D** » Sun Feb 19, 2012 3:06 pm

RWS wrote:what about dissimilar metals in saltwater?

pehaps not an issue as the shaft is stainless and the props are bronze/nibral?

should this be a consideration?

RWS

Most deffinately a consideration. Make sure your bonding system is up to par and ensure corrosion protection hardware is being maintained.

Big D · Post by **Big D** » Sun Feb 19, 2012 3:08 pm

jefflaw35 wrote:stupid ?? since i have not got this far yet, can you tell me what the struts are. or maybe show me a picture, thanks

The part attached to the hull in front of your rudder and prop that suspends the shaft. It has a rubber bearing in it that your shaft spins in.

alexander38 · Post by **alexander38** » Sun Feb 19, 2012 3:13 pm

RWS wrote:what about dissimilar metals in saltwater?

pehaps not an issue as the shaft is stainless and the props are bronze/nibral?

should this be a consideration?

RWS

or add in that S/S will weaken and snap in a O2 deprived area.
and doesn't torque well..

Big D · Post by **Big D** » Sun Feb 19, 2012 3:20 pm

I believe your Carver has SS fasteners here no?

alexander38 · Post by **alexander38** » Sun Feb 19, 2012 3:38 pm

on my struts ? hope bronze no S/S bolts holding anything but bright work..S/S screws for taps on 3 yr replacement sch.

Nancy · Post by **Nancy** » Sun Feb 19, 2012 3:40 pm

Big D wrote:
jefflaw35 wrote:stupid ?? since i have not got this far yet, can you tell me what the struts are. or maybe show me a picture, thanks
The part attached to the hull in front of your rudder and prop that suspends the shaft. It has a rubber bearing in it that your shaft spins in.

Jeff, for photos, do a google image search on "boat struts" (w/o the double quotes). The bearing inside the strut is called the cutless bearing. Do a google image search on "cutless bearing" and you'll see the assembly.

yorklyn · Post by **yorklyn** » Sun Feb 19, 2012 4:01 pm

I was worried about the stainless below the water line. When I took the ss swim platform bolts out they were really bad. The stainless I removed from the one strut was still in good shape but no way of knowing how old the bolts were. Never thought of the bronze being used a the "weak link" but kinda makes sense. I believe the backing plate is stainless(havent cleaned it up yet) so not sure about dissimilar metal. Sounds like bronze is the way to go for the struts.
Second question, how about the swim platform bolts? as stated above the stainless was bad when I removed them. The platform supports are stainless. would bronze be strong enough?
Thanks

jefflaw35 · Post by **jefflaw35** » Sun Feb 19, 2012 4:07 pm

yorklyn wrote:I was worried about the stainless below the water line. When I took the ss swim platform bolts out they were really bad. The stainless I removed from the one strut was still in good shape but no way of knowing how old the bolts were. Never thought of the bronze being used a the "weak link" but kinda makes sense. I believe the backing plate is stainless(havent cleaned it up yet) so not sure about dissimilar metal. Sounds like bronze is the way to go for the struts.
Second question, how about the swim platform bolts? as stated above the stainless was bad when I removed them. The platform supports are stainless. would bronze be strong enough?
Thanks

i just took bronze out of mine. they looke enough to put back in but i will buy new ones, the uppers were stainless, but they dont sit in water

alexander38 · Post by **alexander38** » Sun Feb 19, 2012 4:10 pm

there again I go back to what the factory put in mine are s/s and check them every paint job and as a mandatory replace every 3 years.