Scout 187 porposing

[828mac]

This is 828mac: I purchased a Scout and found with my family of 5 the boat would porpose at any speed. It did not matter where we sat or stood with the motor trimmed all the way down it still porposed. We contacted the dealer and they put trim tabs on the boat. But what we have found now is that we have to trim them over half way down to keep the boat from porposing. The boat has the maximum horse power of 150 on it. Does anyone have any suggestions?

 

[joe009]

Re: Scout 187 porposing

you did not say what motor you have.the 4 strokes are a lot heaver and could cause porposing.i had the same tbl with my 20 ft cc.and did two things to correct the pblm.add trim tabs that you did,and add a good set of hydro foils, which will be better for porposing.i also had a t bag mounted in the t top that was causing a sail and lifting the hull out of the water a little bit and causing some porposing.

 

[gss036]

Re: Scout 187 porposing

Again, what motor are you talking about, if it is new and still in trial/error stage, try using a power tech 4 blade stern lifting. That may solve your problem, especially since you have tabs and hydrofoil. I would not think it would be bow weight that is causing the problem, if it is, then try a bow lifting 4 blade prop. I have one that my son-in-law gave me that came from a SAFEBOAT like the Coast Guard uses, you would not think they would be bow heavy with all the engines on the transom.

 

[rs1lollie]

Re: Scout 187 porposing

I would look at this post b4 buying any hydrofoils. Also you should try to contact hwsiii and he will help you out, it is poss. that your motor is sitting to low or to high and you have the wrong prop http://forums.iboats.com/showthread.php?t=348855

 

[828mac]

Re: Scout 187 porposing

Thanks for your replies: Yes this is a four stroke. Which weighs 60 pounds more then the 115 which was on this boat. The dealer put the two batterys for the trolling in hem. They said that will offset the weight .This boat Has a T-Top and T bag.

 

[scoutabout]

Re: Scout 187 porposing

If I'm reading you right you've got the max size engine on (150 hp 4 stroke) verus the 115 that used to be on it?

Anyway, my observations over the past three seasons with our Scout 170 Dorado is that the boat is more prone to porposing than most outboard boats of its size. There is a very fine line on my boat between optimal trim and beginning to porpose. Sometimes, although rarely, I've found optimal trim under some sea conditions can induce it if those conditions change. Say if I've come in from some open chop to flat water in a protected bay. It's all very controllable -- just more sensitive than what I'd consider "normal" on a boat this size.

Now, that's with running a 90 hp 4 stroke on the hull, well down from the 130 max rating. From this might one reasonably conclude from the comparison of our two similar boats that it's your bigger motor putting you over the top?

Other random thoughts:

I have also often wondered if their Air-Assist hull design contributes to this tendency in my boat. ("to combat the problem of static stability, common on small boats. With additional longitudinal buoyancy, the Air-Assist hull increases static floatation and decreases time to plane and also vastly improves overall handling characteristics..." - Scout sales literature) Although you would think they would have discovered this long ago if it was a factor instead of crowing about improved handling...


Also, did you ever run it with the 115 and if so, did you have the problem then?

You also mention having your entire family on board. What about just you or one other? Any difference?

 

[828mac]

Re: Scout 187 porposing

Thank you for your reply: When I purchased the boat I asked to have the 115 removed and place the 150 on. When I am the only one in the boat I find it fairly easy to manage the boat performance. I don't have to use the tabs very much and I can use my motor trim for maximum performance.

 

[highN'dry]

Re: Scout 187 porposing

Put a Rev 4 17P on it. The t tops is probably contributing. Our BW Outrage will porpoise sometimes and I found that stowing the bimini top reduced the tendency. However, tabs (real ones) and a Rev 4 prop stopped it cold, reduced my planning speed considerably and allow me to trim left and right and bow up and down.

I know it is aggravating but just put the tabs down till it stops. A stern lifting prop like the Rev 4 is very effective also and further contributes to reduced planning speeds and much greater traction.