PULLING TUBE BOAT HANDLING

[SHOTGUN RUSS]

Did not know where to place this post but general seemed the best. I have a 21.5' cuddy with a AQ260/290SP with 15"x19 pitch prop. When I pull a three person tube with about 400lbs of people on it as I am taking off to get up on plane I can give about 1/2-2/3 throttle then the prop will slip. Same if I slow down quite a bit then get on the throttle to about 3/4 and the prop will start to slip. Does this sound right? I am familiar with smaller OBs around 120hp that do not have the torque like the v8 and do not have this problem. Is this just the nature of the boat setup? I can go to a bigger wheel with lower pitch 16"x 17 or 15 pitch would that make much difference? Overall the boat works okay just really have to be on the throttle to keep speed but not slip in heavy load conditions. Thanks for any advise or thoughts.

 

[TyeeMan]

By slipping, do you mean the prop is ventilating? As in it "breaks loose" if you will and your RPMs go up. I wouldn't call that normal. Is the out drive trimmed all the way down? If not that could be one cause. Do you have a ventilated prop? A ventilated prop will have 1, 2, or 3 holes drilled through the hub of the prop. The purpose of that is during a hole shot it allows the prop to ventilate a bit in order for the engine RPMs to quickly rise so the engine gets in it's power band quicker.

That said, I've seen vented props on larger outboards, , can't say so much for an I.O.

One other thing comes to mind, what condition is your prop in? If it's all banged up with pieces missing that might result in the problem your having.

 

[SHOTGUN RUSS]

Yes it "breaks loose", does not have a ventilated prop has the factory elephant ear prop. Leg is trimmed all the way down and prop is good shape, I suspect it is a torque thing with the V8, but I am new to a bigger boat with an I/O and want to make sure this is normal.

 

[Scott Danforth]

vented props dont work on VP drives as the exhaust exits thru the anti-cav plate

where do you have the giant parachute of a tube attached to the boat? the transom towing hook, or the transom tie-down eyes?

 

[tpenfield]

Only does this when tubing? A lower pitch or 4 blade prop may help. Also No need to accelerate fast with tubing. You can work the throttle up slow to avoid the prop slip (cavitation). Can you pull up a skier or wake boarder with this boat?

 

[SHOTGUN RUSS]

Have the tube rope attached to the jumper rope( allows less stress on turns) that is hooked to the tie down eyes. Have not tried skiing or wake boarding, I am sure the boat would be able to pull up both. Yes the tube is big, have several family members that are nervous around water but love to go with their family tubing. Never tried putting full throttle on a normal run to get up on plane to see if the prop would slip, the boat has never needed it. At first I thought a lower pitch might help but, it could make it worse. A lower pitch would give more available torque and cause the slip easier. I can go up an inch in wheel size to give more bite. Thoughts?

 

[tpenfield]

What is the maximum speed that you pull tubers? Remember, water + speed = concrete

 

[Scott Danforth]

try towing from the transom tow eye vs the bridle and tie down eyes. also try to drop your trim tabs a bit to keep it on plane at lower speeds.

also, back off the throttle a bit and ease into it. tubes are to be pulled at 20-25 mph.

 

[SHOTGUN RUSS]

Usually never tow over 30mph most is 20-25mph, the transom tow eye is about a foot higher than the tie down eyes and in my thinking it would only put more leverage keeping the bow high and stern stuck in a hole to get on plane. I was under the impression for tubing use the two tow eyes and skiing using the the higher single transom eye. I do not have trim tabs maybe in the future I might install but will not be for awhile, I have other priorities on my list before them. I do ease into pulling but had tried to see how much throttle I could apply to get on plane and stay on plane in various turns and such.

 

[Scott Danforth]

Try towing from the tow eye

 

[TyeeMan]

I didn't associate the AQ in the original post as Volvo drive. Yeah, wouldn't make a whole lot of sense to have a vented prop (even if you could) if there isn't exhaust exiting through the hub.

Previous boat I had the VP Duoprop with exhaust vented through the anti cav plate.

 

[sweebs]

I'd draw a line with marker across the hub and determine if your hub is spinning

 

[SHOTGUN RUSS]

I will try those suggestions and see what happens, thanks again

 

[QBhoy]

Hi
I'm not totally sure there is much you can do in this case, except perhaps not bank her into such deep turns when tubing. Not perhaps the thought chain you were after but maybe ultimately true.
The VP 290 SP isn't really a performance orientated drive by design. I'm also not so sure you will get a vented prop for this drive (in fact I'm pretty certai , but airing on the side of caution).
Perhaps just keeping the trim right down is your best bet.
All the best.

 

[Dave-R]

As posted, a 4 blade prop should help,and there are even 5 blade props, that I see a lot of. These should give a lot more blade area witch should give a much better bite on the water, at the loss of a little top end speed. Dave-R

 

[jakedaawg]

Post #12 is the place to start before you go spending $$ on a new prop.

 

[ondarvr]

Typically if a prop starts to spin on the hub it gets worse rapidly, especially when being stressed by pulling a large tube with multiple people. So if it spun once or twice like this it would be all over.

 

[SHOTGUN RUSS]

I guess in my original post I was more looking for if the scenario was normal the the drive and size of boat and if there was small things that could be changed to make it better. I am fairly sure the prop is not slipping and all the research I have done on says the Volvo elephant ear props are the best, just getting the right size/pitch for what you want to do.

 

[thumpar]

I have a merc and pull a 3 person tube from the tow eye. Mine has never done what you are experiencing. It is a lot harder to get on plane but doesn't "peel out" like yours.

 

[ahicks]

Usually never tow over 30mph most is 20-25mph, the transom tow eye is about a foot higher than the tie down eyes and in my thinking it would only put more leverage keeping the bow high and stern stuck in a hole to get on plane. I was under the impression for tubing use the two tow eyes and skiing using the the higher single transom eye. I do not have trim tabs maybe in the future I might install but will not be for awhile, I have other priorities on my list before them. I do ease into pulling but had tried to see how much throttle I could apply to get on plane and stay on plane in various turns and such.

30mph = concrete on water. That's WAY too fast for a tube. Most slalom skiers don't like going that fast! Max tube speed maybe 22-24mph - unless they ask you to go faster! Generally that only happens once....