Bow heavy Starcraft...how can I remedy this?

[Allular]

I have a 1960 18' Starcraft with a 115 Johnson. I've redone the interior and moved all batteries etc to the rear because the seats are so far forward and she still rides heavy in the bow. Even after trimming the engine the hull has a huge wetted area. Any ideas on how to get the bow up? Thanks!

 

[JB]

Re: Bow heavy Starcraft...how can I remedy this?

Ahoy, Allular. I'm not familiar with your particular boat, but I suspect you have some unplanned and unwanted baggage in a flotation chamber up front somewhere or under a floor. Open any closed chambers, remove and dry out or replace any foam therein. Find out what is under the floor, it may be water.<br /><br />Good luck,<br /><br />Red sky at night. . .<br />JB

 

[Allular]

Re: Bow heavy Starcraft...how can I remedy this?

Under the bow there is nothing except a few life jackets. The foam under the rest of the boat is new and dry. I talked to the previous owner and he had the same problems but didn't mind it. Since taking possession of the boat I've redone the interior and moved all the batteries he had up front to the rear to try to correct the heavy bow. There is nothing left to move to the rear of the boat. Bear in mind this boat is the old style where the driver and passengers sit way toward the front. I would say in the front third of the boat. Would moving the engine higher or lower on the transom make a difference, etc, etc? Thanks again.

 

[StarChief 64]

Re: Bow heavy Starcraft...how can I remedy this?

Not so much a reply to your question but I recently purchased an 18' 1964 StarCraft StarChief. Do you have a line on where to get owner's manuals etc. Starcraft was no help. Have you hooked up with any others who trade info?<br /><br />Thanks

 

[Jacques321]

Re: Bow heavy Starcraft...how can I remedy this?

It sounds like that 115 might not have the needed power to completely lift the front end out of the water.(although I sincerely hope that isn't the problem)<br /><br />Have you tried a lower pitched prop...say 2-3 ins. lower to increase the rpm's and your top end speed. Maybe that extra speed will get the bow up.

 

[saltwateranglin]

Re: Bow heavy Starcraft...how can I remedy this?

Allular, I had a 19 foot Glastron years ago that did quite well with 115 Merc. It to seemed to have a little bow down problem. That boat didn't have power trim and moving the pin helped the situation somewhat. Later I put trim tabs on her and I was able to get the bow right where I wanted it. Later I picked up a used trim/tilt and really made a nice fully adjustable ride.<br /><br />Jacques321, Installing a lower pitch prop will decrease top end speed not increase it while providing more low end power. Increasing the pitch will give quicker acceleration and more top end speed. Care should be taken that your WOT rpm is falling in line with the engine specs when changing out props. Otherwise, you are risking running the engine in an overloaded condition that can cause premature failure.

 

[MIKE F]

Re: Bow heavy Starcraft...how can I remedy this?

It sounds to me (what do I know?) like a trim problem.You are trimming the engine out-right? Also, do you have the correct prop?<br />Can you get max recommended RPM's with it?

 

[mako]

Re: Bow heavy Starcraft...how can I remedy this?

Seems to me you have sufficient power. Looks like the perfect time to install a hydrofoil such as the Stingray or Dolefin. I Had a 17 footer with the same problem and the hydrofoil worked wonders. Very easy install and well worth the 25 dollars or so.Good Luck!

 

[crazyray2]

Re: Bow heavy Starcraft...how can I remedy this?

think you guys have hit on several good options.......one you may try as a last ressort is to try an different style prop....even with the same pitch an prop can be turned to actually lift your bow and reduce your wetted area....it is not clear weather you have tilt/trim or not....if not thats should be your first step.......but just like the tires on your car can make an huge difference in its performace so can an prop do the same for your boat

 

[zorro1]

Re: Bow heavy Starcraft...how can I remedy this?

It is I would say 99% cirtain the outboard trim.Place the pin one position aft and try it. Another if still bow down. You shouldn't need a third but if you do keep going . If you get to the point where the prop is cavitating then you have eliminated the possibility of trim.<br />Above all remember that with anything that has a multitude of remedies its a process of elimination. Trim is the easiest and most possible.<br />Good luck.

 

[evin300]

Re: Bow heavy Starcraft...how can I remedy this?

What kind of prop are you running? Try a raker (OMC), If using power trim you can use trim extenders which would add another 5 deg. positive trim. Just some thoughts.<br /><br />PS If you are using a standard aluminum prop, then the Raker will make a big difference, enough difference? hard to say, borrow one from a dealer.<br /><br />The only other choice would be to set the motor back with a bracket, but you better have a real good transom, I would try the bow lifting prop first (pitched to the upper end of RPM range) Then the extenders, (Land & Sea) Good Luck

 

[bruoff]

Re: Bow heavy Starcraft...how can I remedy this?

One additional idea. There very possibly could be a "Hook", in the bottom. Take a straight edge and hold it parrellel to the<br />length of the boat, hold under the transom and extending forward. If there is a gap between the straight edge and the bottom of the boat, the "Hook" can be driving the bow <br />down under power. This is potentially dangerous if the boat is overpowered. Check the last 18" moving the straight edge parrellel to the length of the boat. I had <br />a boat many years ago that would push the <br />nose down. Checked the bottom and found the <br />culprit! Hope this helps eliminate one potential propblem

 

[Ranger354]

Re: Bow heavy Starcraft...how can I remedy this?

My father had a bass boat years ago that was designed with a hook in the bottom. I never did like that boat! Try the motor trim ideas as mentioned above. Start with the cheepest (moving the pin) and go from there.<br /><br /><br />Water is warm, come on in!

 

[Allular]

Re: Bow heavy Starcraft...how can I remedy this?

Wow! Thanks for all the input! First off, Starchief 64, I haven't been able to find any Starcraft info yet. I don't even know which Starcraft model I have. <br /><br />The 115 has ample power for this boat. Originally it had an 85 Envinrude. It's running a stainless steel prop that tachs out at 5400rpm with 44mph top speed. That was achieved with 3 people, 18 gallons of fuel, 3 batteries, 48qt cooler(full) and a 25 gallon livewell on board so everything seem good on the power and prop idea?<br /><br />The engine has tilt and trim as well. It starts sucking air way before it hits tilt. <br /><br />I do believe there is a hook in the hull but I had never given it any thought to it correlating to the bow heavy problem. <br /><br />I'm glad to hear a suggestion for the stingray or dolefin because they're cheap. I had gotten a suggestion for trim tabs but didn't like idea of shelling out the money for them and still having a problem. I guess I'll start with the stingray/dolefin for now and see what happens. I'll try to keep you up to date on how it works. Thanks again guys!

 

[evin300]

Re: Bow heavy Starcraft...how can I remedy this?

Allur, This is what your reply tells me:<br /><br /> Your motor is mounted to high, you should be able to trim all the way out without sucking air, I you are sucking air, there is a good chance the prop cant provide enough thrust to lift the bow. You should check the hook just to see what it measures, as mentioned earlier.<br /><br />I dont know about anyone else, but IMHO, trim tabs, and doel fins are for stern heavy and hard to plane boats.<br /><br />PS Your boat seems to be putting out some good numbers, what is wrong? Are you getting bow steer? un-controllable bow drift? To much spray?

 

[evin300]

Re: Bow heavy Starcraft...how can I remedy this?

Jusy a few questions: <br /><br />When you say "sucking air" are you refering to a drop in cooling water pressure? or prop slip? (cavitation)<br /><br />What brand and pitch is the prop? Is there any damage, or nicks?<br /><br />How high above or below is the cavitation plate in relation to the bottom center of boat?<br /><br />Is there any obstruction upstream from the prop? Like a speedometer pickup etc.<br /><br />Do you know the gear ratio of your lower unit?

 

[Allular]

Re: Bow heavy Starcraft...how can I remedy this?

The motor is mounted flush with the top of the transom so it can't be lowered without cutting some away. I checked on the hook with a straight edge and it all looks straight! Optical illusion I guess. <br /><br />I do experience bow steer. It doesn't take much chop to cause a rough ride and lot's of spray. <br /><br />When I say sucking air I mean prop slip. The prop is an OMC 13 3/8 x 17 with no serious wear, nicks or gouges. <br /><br />The antiventilation plate sits about 1/4inch below the hull although there is a keel running the length of the boat that is approximately 1 1/4 inches tall. I don't know the gear ratio. It would be whatever came stock in an 85 Johnson 115.<br /><br />When I get a chance I'll take a snapshot of the boat so you guys can see exactly what this beast looks like. Thanks again.

 

[evin300]

Re: Bow heavy Starcraft...how can I remedy this?

Yes, a picture would be nice. I assume the prop is a 3-blade SST (black color). So far, based on the info provided I would definatley try a OMC Raker, or similar. You could try to add more cup to the existing prop, but I dont think it will help enough.<br /><br />You need the high rake (swept back) blades to get performance in a high trim situation. From what I can see, you need lots of positive trim! As you are trimming your motor out you are cavitating, rather than lifting the bow, your prop cant hang on long enough to do the job.<br /><br />PS What is the recomended RPM range for the motor?<br /><br />What is the best top speed and RPM you achieve with a normal load in the boat?

 

[Ranger354]

Re: Bow heavy Starcraft...how can I remedy this?

My fathers first boat was a Delta with stick stearing in the front and a 40 hp evinrude on the back. He weighed 260 and if the water got rough look out! It didn't matter what horse power or prop you had, that thing would knife through the waves. Some boats are just designed wrong. Too much weight in the front no matter what you do.

 

[Hooty]

Re: Bow heavy Starcraft...how can I remedy this?

Okay. I'll guess-a-long with everyone else.<br />Originally 85 hp. Now 115hp.= engine change. Engine is all the way down on transom. "Can't lower engine without cutting transom". When trimming, "cavitates way before tilt".<br />Cav plate is 1/4" below bottom and boat has 1 1/4" keel.<br />Hummmm. I don't suppose that's a short shaft engine on a long shaft transom.<br /><br />Naaa.<br /><br />c/6<br /><br />hooty