Just got into open ocean paddling.do these big 14 foot downwind boards breach (nosedive) a lot in swell. Wondering if their is any things l need to know before l venture out into the sea.

For ocean paddling it depends on the board, and whether you are going into, across or with the swell. Start in bays or protected location with light winds and work from there. Experiment with moving your feet to trim the board. For ocean downwind paddling have a look at the 'Need help with your DW skills?' thread and video. Depending on the board there can be considerable footwork to keep the nose up, as well as other reasons for moving around.
In terms of things to know:
- Wear a (reliable) leash. Without it your board will disappear much faster than you can swim.
- Consider a life vest (may be a legal requirement depending where you live) and hi vis.
- Try and do some ocean paddles with more experienced crew, especially if doing downwind runs. Don't do these solo, it's no where near as fun anyway.

Some worst than others ...When it starts going under run to the back if running with the swell.
attack the swell at a good angle .straight on.a little bit off and it will swing your nose around
and throw you off.

keep it moving at a steady pace ..that's all I know .
get into it .its like surfing in slow motion .

Did my 1st dw not long ago and did the nose dive because I stayed on the same spot and didn't move back (surf stance I think). Have a look this link below gavnwend.
www.seabreeze.com.au/forums/Stand-Up-Paddle/SUP/Need-help-with-your-DW-skills-?page=1#4

If you are using a board with a "boof" nose it will start to nose dive, but then the buoyancy of the nose will start to work in your favour an lift it up MOST of the time, you just have to learn to trust it.

Thanks for the replies everyone.the board l will be using is a current 2017 fanatic falcon 14 .got a good deal on it. l won't be going out solo on it (offshore) .l must admit the newer ones are a lot stable & motor downwind.should of took it up years ago.