Pontoon posts?

[IanMcKay1]

Hello everybody, I am on the scrounge for advice. I have to replace the upright posts of a pontoon jetty, the lower 18 inches of which are permanently under water, the rest being out of water, supporting the decking etc. The existing posts, which are fast approaching the end of their life, are 7" by 7", and 80" long. I was thinking of ordering oak or iroko, unless you guys think otherwise. Any suggestions please? Thanks.

 

[sw_edge]

Is the jetty in salt or freshwater? Greenheart would traditionally be used in coastal locations for this kind of structure although oak sleepers would probably be fine in freshwater.

 

[IanMcKay1]

Thanks for the reply SW. The pontoon is over a freshwater lake, rainwater.

 

[AndyT]

In Venice, where they have rather a lot of posts partly submerged in the water, they use sweet chestnut, so that could be a good choice.

 

[woodfarmer]

Some elm drain pipes from Roman times supplying water are still good. But elm needs to be always wet, th bit out of water might rot.

If you can find it Greenheart would probably be best. after that as said chestnut. I use them for fencing posts due to their non rotting nature, also acacia (robinia).

 

[sw_edge]

Otherwise (no where near as pretty) I've seen scaffold poles driven in to the bed....

 

[Harbo]

+1 about Elm - Winchester Cathedral was built on waterlogged ground sitting on Elm logs - still standing after 935yrs though a diver did do some repairs at one end a few yrs back.

Rod

 

[IanMcKay1]

Thanks all for the replies there, that's given me some confidence in what to talk to the local timber yard about.

 

[maltrout512]

If I can remember the size about 200 mm square and green oak. I drove them in about 300 mm after putting a point on them.

The post to the right is the inside corner of the L shape.

I quite enjoyed this job, never worked in water before.

And the finished article

This was all done over six years ago and is as strong now as when I made it.

 

[IanMcKay1]

Wow! That looks a nice bit of work...."

 

[maltrout512]

Wow! That looks a nice bit of work...."

Thanks..Hope it gives you some idea.