2001 268 Islander very unstable.

[Mustang65fbk]

I did notice that on my neighbor's boat that the issue wasn't as bad when he filled up the tank entirely, though he still did have some lean to one side of the boat, almost like one tab was all the way up and the other was all the way down. A couple weeks after he filled up though, it was noticeably worse, and that's when I tried driving it in the comment that I made above. There were 4 of us out fishing on his boat that day and even if everyone was sitting down with minimal movement, we'd still have the issue of it pulling to one side or the other. My boat doesn't do that and you'd think for a boat that weighs a couple thousand pounds more than mine, that it wouldn't have that issue at all, even if you had a couple people moving around some. My boat didn't even do that when I had 10+ people out on it in the summer of 2022 and adults/kids were walking all over it even when underway.

 

[SeanC]

So when you say it is leaning from one side to another does the bow continue to track straight or is the boat weaving? If it is weaving then it sounds like bow steering. More weight towards the transom trim tabs up a motor trimmed out would help.

If the boat is tracking straight does it occur in flat water or is it when you are crossing a wake or chop at an angle (coming from the side) If it occurs crossing wakes or chop it’s most probably due to a high centre of gravity. More weight down low should help. The use of tabs can stiffen the ride up.

 

[Peter A]

A couple of thoughts. Auto trim tabs might help, provided you establish settings after proper motor trim. Second thought is prop selection and motor height. Since I don’t have an Islander I can’t comment on the right combination but @Hookup1 or other drivers of this hull might have combos to compare to your setup. Less lift in the back? Something is not right. The Grady hull design generally seems sensitive to trim. Different boat but my 208 was much more stable on trim after a prop change. Getting the slack out of steering and confirming good motor alignment and synchronization would be good if not done already.

 

[family affair]

I can't say for the 268, but can say for certain on the 270, tabs make this issue worse. I haven't been able to determine exactly what forces are at play when this happens, but dropping a tab to raise the low side actually makes it worse. Rather than the tab lifting the listing side, it creates more drag and makes the hull pivot.
In my case, I'm confident it is a weight issue. Full fuel tank(s), water tank, people, and engine weight made the problem go away. As others suggested, I would suspect other variables like props, engine trim, wind and sea states can contribute too.
When it occurs it is unnerving, but I haven't experienced anything unsafe when it decides to lean. A quick snap of the wheel brings it back to center and I want to say trimming up helps to get the stern planted.

As for tab use, rarely do I need them in anything 2' or less cruising 28 mph +. 2-5' I use them often in anything but a following sea. Unlike some of the other GW hulls, 16-25 mph performance is excellent with the tabs dropped.

 

[Mustang65fbk]

So when you say it is leaning from one side to another does the bow continue to track straight or is the boat weaving? If it is weaving then it sounds like bow steering. More weight towards the transom trim tabs up a motor trimmed out would help.

If the boat is tracking straight does it occur in flat water or is it when you are crossing a wake or chop at an angle (coming from the side) If it occurs crossing wakes or chop it’s most probably due to a high centre of gravity. More weight down low should help. The use of tabs can stiffen the ride up.

I'm not sure if this question is aimed towards me or not, that being said on my neighbors 270 Islander, the bow would definitely list one way or the other and definitely had quite a bit of bow steer. I only have a little bit of experience on his boat and driving it, but it did very much seem like the bow was quite squirrelly. Some more weight in the stern could potentially help out a bit, though I'm admittedly no expert on the matter.

 

[family affair]

The fact that the 275 uses the same hull with 4 cylinders and no reported issues would support the weight theory - at least for the 270s.
I've never heard of anyone complain about a 273 either.

 

[SeanC]

I'm not sure if this question is aimed towards me or not, that being said on my neighbors 270 Islander, the bow would definitely list one way or the other and definitely had quite a bit of bow steer. I only have a little bit of experience on his boat and driving it, but it did very much seem like the bow was quite squirrelly. Some more weight in the stern could potentially help out a bit, though I'm admittedly no expert on the matter.

Questions were for the OP.

 

[jjack5150]

I occasionally had that issue. Was as if everyone suddenly moved to one side (no one on board!). Found that with trim up approx three bars and no tabs solved it somewhat. Then I installed auto trim and the issue went away.

 

[Gulffisher]

Please rethink your problem more specifically and consider some possible causes listed (no pun intended) below:

When sitting still does your boat sit level or list? Improper loading, including anchors, chains, fishing gear (weights), dive gear, and fixed equipment like batteries etc. Passenger loading.

If boat lists only while underway, is the list consistently to the same side? Motors not trimmed equally, look at motors (not trim indicator) and confirm. Props are not the same pitch/diameter. One prop may be spinning on hub. One engine may not be developing equal power. Boat hull has a hook or rocker from improper trailer/rack storage. Hull was warped during a floor/deck replacement.

Is the list abrupt and swaps from side to side as you hit waves? Bow heavy from improper loading. Bow down from insufficient up-trim on engines. Bow down from too much (any) trim tab. Hull has hook/rocker from improper trailer/rack storage or was warped during floor/deck replacement.

There are certainly other issues but these come to mind immediately. While not at all the same boat, my 2001 22' Dauntless can be a bit scary in quartering seas when the engine is trimmed down. My 330 GW express also likes to to have the engines trimmed way up and NO TABS. Don't be afraid to trim up until just before props aerate or slip if that raises the bow. I have no direct experience, but I have heard some prop designs are better/worse at helping with bow rise. You might try different props.

 

[oldmanriver97]

So when you say it is leaning from one side to another does the bow continue to track straight or is the boat weaving? If it is weaving then it sounds like bow steering. More weight towards the transom trim tabs up a motor trimmed out would help.

If the boat is tracking straight does it occur in flat water or is it when you are crossing a wake or chop at an angle (coming from the side) If it occurs crossing wakes or chop it’s most probably due to a high centre of gravity. More weight down low should help. The use of tabs can stiffen the ride up.

the boat just starts to roll towards one side or the other. maybe dependent on wind? but even on flat water shell do it and to make even the slightest adjustment with trim tabs it rolls to the other side. may be the additional weight , Garmin , two radios, Furuno all on the hard top could add higher center of gravity. fishing for clues thanks for the input brother

 

[oldmanriver97]

Please rethink your problem more specifically and consider some possible causes listed (no pun intended) below:

When sitting still does your boat sit level or list? Improper loading, including anchors, chains, fishing gear (weights), dive gear, and fixed equipment like batteries etc. Passenger loading.

If boat lists only while underway, is the list consistently to the same side? Motors not trimmed equally, look at motors (not trim indicator) and confirm. Props are not the same pitch/diameter. One prop may be spinning on hub. One engine may not be developing equal power. Boat hull has a hook or rocker from improper trailer/rack storage. Hull was warped during a floor/deck replacement.

Is the list abrupt and swaps from side to side as you hit waves? Bow heavy from improper loading. Bow down from insufficient up-trim on engines. Bow down from too much (any) trim tab. Hull has hook/rocker from improper trailer/rack storage or was warped during floor/deck replacement.

There are certainly other issues but these come to mind immediately. While not at all the same boat, my 2001 22' Dauntless can be a bit scary in quartering seas when the engine is trimmed down. My 330 GW express also likes to to have the engines trimmed way up and NO TABS. Don't be afraid to trim up until just before props aerate or slip if that raises the bow. I have no direct experience, but I have heard some prop designs are better/worse at helping with bow rise. You might try different props.

when i bought the boat the owner (seller) said it tends to lean and i should keep the forward tank full to help steady the ride. the one thing I've found is when making a turn the outside motor tends to increase rpms while the inner keeps rpm stable. this boat is the first twin outboard I've owned so still in the process of learning its tendencies. i sure do like how easily i can maneuver into and out of the dock and my slip. thanks for the input brother

 

[seasick]

If the outside motor seems or actually does increase revs, most likely the prop has broken the surface of the water. The prop blows out, looses bite ( slips more) and the thrust is reduced. Now you have unbalanced thrust. In the case where the boat is steered to starboard, the port motor in the turn looses thrust. The greater thrust of the starboard motor tends to turn the hull to port but you want to turn to starboard. This unbalance causes the hull to roll to port as well as steer to port. The tendency to roll can be extreme and unsettling.
I do not know if your hull is prone to this situation by design or if the configuration/trimming of the boat is a factor.
Obviously keeping the props under water in turns is important. Moving weight forward may not help but adding weight by adding gas to the forward tank may. Remember that the goal is to keep the outer prop on a turn under water. Trimming the bow down may make the problem worse if it raises the transom when on plane. Same thing goes for the trim tabs. Deploying a lot or even some of the tabs can lift the aft end.
I suggest that you check a few things first regarding rigging.
This may sound dumb to ask but do you have the proper length motor shafts?
Are the motors spaced as per the rigging spec?
Are the motors mounted too high?
Is the toe out set to spec. Contrary to what a lot of folks call it, toe out is when the prop shafts of the motors are slightly closer together than the steering links. When set correctly (for Yamaha motors) when on plane with motors trimmed perpendicular to the water, there should be two wakes behind the boat. The two wakes should merge somewhere from 15 to 25 or more feet behind the boat. If the wakes instead of crossing, continue to diverge. that condition can greatly increase handling instability.

 

[Ekea]

^ x2. both props should stay in the water on a turn. check the things he mentioned.

 

[family affair]

My df200s would do the same in turns until I brought the prop shafts closer together. Tracking and stability seemed to improve also.
The 268 may be different, but the 270 is better off with the front tank empty and the rear full. In your case this should bring the stern deeper into the water potentially helping to avoid the prop from losing traction.
As for trim, I'll trim up for efficiency, but trim lower when turning to avoid prop ventilation. I'd love to tell you these are hard and fast rules, but it can be load, speed, and condition dependent. To get acclimated to my boat, I went for a couple trips solo, wore my pfd and lanyard, and started experimenting with speed, trim and tabs. I found the sweet spots and use those for my reference points. If you haven't sufficiently played with those settings and checked the parameters mentioned, you might be scratching your head for a long time without much improvement.

 

[Halfhitch]

The way you describe the listing, it sounds just like a hull that is overloaded. When a hull gets close to it's maximum displacement, it becomes unstable. Could it be that your boat is water-logged and with just normal everyday items on board the hull is over its capacity? Just a thought. Have you weighed it?

 

[DennisG01]

You definitely shouldn't be getting ventilation when turning. I'm not sure if that will "cause" your issue, but it's something that should be addressed, regardless. Maybe you'll get lucky and that's what causing the issue. Drop the motors a hole or two. If you have the boat on a trailer, put a straightedge on the bottom of the hull and extend it to the anti-ventilation plate and post a picture or two of this.

Do you have anyone nearby that has a similar boat (and has lots of experience with this style)? Take them along and let them play with it - see what happens.

 

[oldmanriver97]

The way you describe the listing, it sounds just like a hull that is overloaded. When a hull gets close to it's maximum displacement, it becomes unstable. Could it be that your boat is water-logged and with just normal everyday items on board the hull is over its capacity? Just a thought. Have you weighed it?

as far as being waterlogged, I hope it isn't. i did a lotta research as to the history of this model and year. i looked, sounded and checked to the best of my knowledge the condition of the hull and transom. i find it amazing that I've got cobwebs in the bilge. she's been dry as a bone all summer. while she's propped up in the driveway for winter i may just weigh it come springtime. I very much appreciate all the input thank you and have an enjoyable holiday season

 

[Toothpick 10]

scary stuff rolling to one side or the other even at part throttle. trim tabs seem to be less than helpful. It appears to me the islander hull is deep vee while not as broad of a beam as other models. anyone else experience the same problem?

I have the 2002 Islander 270, and find it to be quite stable under most conditions. I just have the single OX66 250 HP, which should make mine less stable than yours. I always start the day with the tabs all the way up. If I am getting a little list due to wind or weight distribution, I will apply very little tab to one side to level her out. When cruising, I follow the instructions that I have found on GW videos online, that is I apply the throttle to get the boat up on plane, once I get up to about 20 mph, I start trimming up the motor until I just start to hear it ventilate, then trim it down slightly until it stops. I usually cruise from 25 to 30 mph depending on the sea condition.

My Islander does do much better in a head sea than a following sea. If you get in a following sea with 3 or 4 footers, you will be white-knuckling it.

The main key is trim tabs up and motor trimmed up until the ventilation point, which is 4 or 5 bars on my Yamaha gauge.

 

[Fishtales]

GW uses the same hull on several variations (CC, DC and WA) of boat models. Would not surprise me if there are a few sub optimal combinations out there....

 

[Gulffisher]

Many people think motors need to be trimmed in and then want to use tabs. They should buy a trawler if they like pushing water around..