Towables

[Vertigo]

When pulling a towable and during a turn, the motor will rev higher. Almost as if the prop has come out of the water. Any ideas on what is happening?

 

[mlpaskett]

Re: Towables

It does sound like your prop is ventilating...or coming out of the water. Keep trim all the way down when tubing etc.

 

[Vertigo]

Re: Towables

When you mention "keep trim all the way down". Do this mean that I normally would keep the trim in the middle, but for towing I would keep the needle at the bottom? I have been told that there is a spoiler type mechanism that can be fitted just above the prop. Are you aware of this item?

 

[mlpaskett]

Re: Towables

Trim is something that should be adjusted each time you stop the boat and start up again. It is generally best to put the trim all the way down when coming up on plane...starting from stopped. As the boat gets on plane the trim can be adjusted up a little. This enables the boat to lift up a little higher on the surface of the water thus improving performance and fuel efficiency. When the prop is trimmed too high it can ventilate or "come out of the water". When this happens, you should trim down until the prop "gets traction" again. While tubing and doing a lot of turns and such ventilation can easily happen that's why it is a good idea to keep the trim all the way down.

I have seen and even used the "spoiler" you talk about. I guess it is possible that one of those could help, but often times there are other performance drawbacks to using them. They create A LOT of extra drag and some report of stability problems at high speeds caused by them. You will likely be able to control you ventilation problems without one as you practice and learn to properly trim your boat for each situation you boat in.

Search this forum for "trimming you boat" you will find lots of info and tips about trimming.

 

['78 Crusader]

Re: Towables

The "Spoiler" you're talking about is a Hydro foil type deal. You don't need them.

When towing something, anticipate your turn and lower your trim. You do not need to lower your trim all the way down, just enough to prevent the prop from ventilating as mentioned above.

There's no set secret to do it....just have to play with the trim as you're towing things.

 

[Vertigo]

Re: Towables

Awesome feedback!!!!
Thanks,

 

[204 Escape]

Re: Towables

The 225 Merc outboard that we had before had a hydro spoil on it, when we bought it. I thought that it made a "line" behind a tube that made it rougher on the tube rider. We are using the same tube on a I/O and do NOT see/feel this same situation.

IMO, those may be O.K. in certain situations, BUT, for the most part with trim, etc., "I" do not feel they are needed.

 

[sw33ttooth]

Re: Towables

i put a hydro foil on my last boat it was a 90 hp v4 and i noticed a differnce, turning seemed like the boat didnt rock back and furth so much and it made the prop run at a lower rpm. as for what the companies tell you that they increase fuel, no they dont, or increase hp and or/speed, again false felt like i was going faster but accually since my rpms droped i lost about .5-1 mph. to the trim part, keep outdrive all the way down more power if your cruising fine trim it up, but for sports or heavy loads best to just keep it all the way down.
looking back the $70 i spent on that hydro foil was a big waste, kind of like putting a spoiler on a handa, wont be usefull untill you hit the 100+ mph which is illegal in the USA.