SUB question -Kill the engine?

[jumpjet]

First off this is my first summer using a stand-up. I have a bone stock '08 SJ, and I am getting good at flat water subs on command.

So is it good practice to leave the engine on during a deep sub? Sometimes my speed is too high and it will make me go too deep (so deep, the boat is pointing straight down and I'm hanging on superman style completely submerged). During this underwater maelstrom, I still hang on but I lose my footing. My first reaction is to kill the engine since the boat is completely submerged and I wont be riding it out. Is this a good reaction?

I love subing the boat, but if its hard the equipment I would be much more inclined not to do it.

Thanks for the read and help on this matter.
jumpjet

 

[Drav]

Get a bilge pump first of all...and keep it running...theres no reason to kill it unless you ingest a large amount of water where you might risk hydrolocking

 

[jumpjet]

so a deep sub doesn't give a good risk of hydrolocking?

 

[SJBrit]

You're fine. You actually need the engine to do a decent sub: one blip to half throttle gets you down, the second gets you level, and the third points you back up. Remember to keep riding the ski under water and you'll come out straight. The best insurance against water ingress is to close off the front breathing holes in the hood if you're still running the stock RN hood.

 

[demolition_x]

just when your done subbing don't fall off and flip the ski on the right side cause theres a good chance if theres a lot water inside the carbs could suck up some h20.

so if your feeling like your gonna fall to the right kill the switch or yank the lanyard

 

[jumpjet]

Thanks for the info guys! I will not fret to much for my noob subs.

I'll look into a bilge pump this winter.

For the time being, how effective is the stock water removal system?

 

[SuperJETT]

Be careful though, you can hydrolock an engine. I had a hood liner fail while under and it cracked my cylinder plus bent my crank.

 

[SJBrit]

Be careful though, you can hydrolock an engine. I had a hood liner fail while under and it cracked my cylinder plus bent my crank.

Bu that's with a Polaris hull... :439:

Jumpjet - get yourself at least 1 bilge pump before you start to do this: you'll get a lot of water in there, and the only way to know for sure that it's all gone is when you see the water stop flowing from the bilge outlet. The problem with the stock siphon is that you have to guess, and you really want the ski to be empty when you start your next trick. Two subs in a row without emptying in between spells trouble.

 

[jumpjet]

I'll definitely spec a sick pump this winter.

You make a really good point about how you have to guess without one. Usually I just ride relaxed and stable for a while before I attempt another maneuver.

thanks again.

 

[Swooperjet]

If you're going to still be doing plenty of riding before you hang it up for the season, I'd get the bilge pump now rather than this winter. You can pick up a 500 gph for pretty cheap, and it only takes about 1/2 an hour total to install. Very cheap and quick insurance policy.

 

[goldmullet]

SJBrit, if you close off the holes on the stock hood where will it be drawing enough air from during normal topside running??

 

[SJBrit]

You can open out the rear holes to get some more air in to compensate.

 

[Speleopower]

I have a sort of bone stock SJ. It doesn't have any engine mods. Put in a bilge pump and epoxy in the holes that are covered by stickers in the back while your at it. You should also cover the front holes in the hood at least with duct tape or better yet some sticky back turf.

You will get enough air in the run with the front holes blocked off at least on the stock engine setup.

The bilge will get the vast majority of the water out and then if you ride straight and level for a bit the stock system will get the last bit out for you.

Scott