Bow Down, PLEASE!!

[Klemdog]

I just bought a Crestliner 14SC w/ a 25HP fourstroke outboard. Power trim and tilt, etc. The prop is 9 7/8 x 9-F and when it finally planes out it is turning roughly 6000RPMs @ 19 - 20MPH. The bow stays in the air for quite some time before it planes out...I'd say for about a minute or two, then it likes to porpoise on fairly calm water. I checked the motor mounting to include the bolt is in the lowest hole on the power trim bracket, the cavitation plate is 1 inch below the bottom of the boat and the rpm range (according to the book) is 5000-6000rpm. Maximum output is 25HP @ 5500RPM. <br />I also had the power trim all the way down and made several test runs from a stop and from slow moving to moderate movement...all producing the same result. I did notice the motor will struggle to get the boat on plane and then does fine until I slow down slightly or turn. Then back to bow up again. <br />What should I do to fix the bow up attitude? Would installation of a Whale Tail or Hydrofoil fix this...and/or will this void my warranty? Should I shift some weight to the front of the boat...like batteries? Any help would be appreciated.

 

[suzukidave]

Re: Bow Down, PLEASE!!

You have pretty common symptoms for a light aluminum boat with a big heavy 4 stroke on the back, especially if you are tiller steer? I suspect your boat is not able to fully plane until it bounces itself on step and then is vulnerable to being bounced off. Usually you cure all this by trimming the motor tighter in to the transom -- it sounds like this won't work for you.<br /><br />Weight at the front is the cheapest option if it works. Try a friend or some sandbags. If this works you might consider keeping your fuel up front.<br /><br />A dolefin or similar hydrofoil is another pretty cheap option that many on this site swear by although the mounts can damage your motor's lower unit. I suspect a dolefin would cure your holeshot, bow and porpoise problems while cutting speed 2 or 3 mph and burning more gas because of the increased drag.<br /><br />A jackplate that extends the motor up and back from the transom is a third option that will probably work. The cavitation plate should line up with the bottom of the V at your stern so you are hanging low and this may be part of your problem. A jackplate is not as sure a cure as a dolephin but if it works it will never damage your motor or increase drag -- in fact it will speed you up.<br /><br />Otherwise you are into pricier options like a 4 blade prop, manual trim tabs or switching to remote steering.<br /><br />I'd try a jackplate first since its a purer solution if it works. However, many would say just try the dolephin.

 

[f_inscreenname]

Re: Bow Down, PLEASE!!

Trim Tabs (Bennet) will help and are easy to install. I would still move anything that was not bolted down to the bow to if I could get it over. It seems that you have a very under powered boat for the size or very unbalanced.

 

[Klemdog]

Re: Bow Down, PLEASE!!

My boat does have remote steering by way of a side console. It also has power trim...so doesn't this mean it has the jackplate you are referring to.<br />I have installed a hydrofoil onto the outboard, but have not had it in the water yet. I am also in the process of relocating the batteries up front. Hopefully, this does not put any strain on the charging process from the outboard.<br />Comments?

 

[suzukidave]

Re: Bow Down, PLEASE!!

sorry klemdog, I was away. Did the hydrofoil do it? To answer your question, a jackplate is not the same thing as power trim. It attaches to your transom and then you attach your motor to the jackplate. It allows you to adjust the height of the motor without cutting or drilling your transom and also lets you set the motor back from the transom into "cleaner" water where it performs better. You say your motor cavitation plate hangs 1 inch low of your hull - it will perform better at least even with the hull but you need to raise the motor mount somehow -- either use a jackplate or remount the motor on the transom with a spacer-- the only way the power trim can raise the leg is if you trim the motor out which will aggravate your porpoising and poor planing. Also, if you go back 5" with a jackplate you can raise the motor another inch above the hull bottom which will improve performance. Overall your performance will improve from a jackplate. The real question is how much. I believe you tend to get greater improvements on bigger boats than yours.<br /><br />As for the battery, I don't imagine that your starter draws a lot but make sure you use the recommended guage of wire for the new distance and have good solid connections.

 

[Klemdog]

Re: Bow Down, PLEASE!!

Sorry for the delay...work has had me tied up all week. <br /><br />The hydrofoil worked!! It kept the nose down so well I had to trim up a little. Plus I relocated my batteries up front. Which, I believe, has balanced out the boat quite well. It just leans starboard somewhat, but a little adjustment and that will be fixed. ANyway, it worked and I'm happy. Really surprising at how fast it gets up on plane now and how much better it turns also. No more porpoising too. Runs smooth as silk.<br /><br />And get this: I called the dealer and they said since they take care of the warranty work, the installation of the hydrofoil will not void the warranty on the outboard. Even more good news.<br /><br />Thanks for your help, to all. Happy Klemdog!!