Boat squatting at WOT

Bobjr1261 · Post by **Bobjr1261** » Tue Sep 18, 2018 4:53 am

Recently went for a cruise and decided to open her up on the way back to home Port. When I reached around 27 mph the boat listed considerably to starboard and I immediately backed off the throttles . Has anyone else experienced this? Any suggestions? Fuel tank was 3/4 and water was at 1/4. Just two people on board both on the bridge and weight equally distributed. Cummins 6bs 300 hp, ZF 220A 1:5 gears

IRGuy · Post by **IRGuy** » Tue Sep 18, 2018 6:27 am

I think it is normal that our boats heel to one side or the other at high speeds because when it planes there is so little wetted surface supporting it it can't stay balanced on that small centerline area. Just my opinion... I am not a marine architect. My FBC with Cummins 6B 315 does the same as yours. Not an issue for me.. how often are the sea conditions going to allow you to run 24 knots anyway?

Post by **dougl33** » Tue Sep 18, 2018 8:48 am

Bob, What were the conditions? Were you in the middle of a turn? Where the tabs down or up? Was there a lot of water in the boat (i.e. rain water or leaking stuffing box or other fitting)? While I agree with some of what Frank says above, if the seas were flat calm, rudders straight, tabs up, and nothing sliding around, there should be no reason for the boat to lean to one side or the other.

Bobjr1261 · Post by **Bobjr1261** » Tue Sep 18, 2018 9:50 am

Doug, Seas were no more that 1 to 2 in the Bay. Running north with southerly wind and following seas. No excessive water. Pumped dry before I went out and no excessive water once I returned. At first I thought it was a rudder malfunction but upon inspection everything was good. Trim tabs could be the culprit maybe starboard side isn't going down as fast or far as the port. I'll have to take a peek the next time Im at the boat. At 21 MPH on plane she's straight as an arrow and level from P to S. IR, I have heard that some deep v's do this, but it is disconcerting when everything wants to go to starboard at that speed. Perhaps being up high on the bridge compounds the affect. Curious if this is normal occurrence or something mechanical. Thanks for the reply, I'll investigate further and keep you updated.

Post by **dougl33** » Tue Sep 18, 2018 10:41 am

I've had the boat lean over to one side at high speed when using the tabs to bring the bow down, and/or I made a course correction, hit a wave, something (or someone) big shifted, etc... I think you're right to suspect the tabs.

richcatch22 · Post by **richcatch22** » Tue Sep 18, 2018 3:49 pm

You have to distinguish between normal operation, in all sea condition, versus abnormal behavior. I cruise all day at 25 knots in all seas. At higher speeds the chine walk is more noticeable, but normal and to be expected. At higher speeds keep the tabs up and try in different seas to get used to normal behavior. Tabs down will make it worse at the higher speeds and the bow comes down. Hull was designed for 18-22 knots

Bobjr1261 · Post by **Bobjr1261** » Tue Sep 18, 2018 4:01 pm

Captain Rich I think you hit the proverbial nail on the head. Next time out I’ll run at WOT without the tabs down and see what happens. Thanks to all for the valuable input

franklyprice · Post by **franklyprice** » Wed Sep 19, 2018 4:09 pm

The tabs should not be used at high speeds. The tabs on these boats were purposely designed to have limited travel and limited surface area. Over the years many owners have added larger tabs to get the bow down for more "efficiency" . This does help get the bow down at cruising speeds, while decreasing the side to side stability. However, over maybe 20 knots, running with the tabs down, especially larger than stock tabs, would not be a good idea. In my opinion, the boats don't need tabs. Kind of handy to level it out to correct for load or wind but other than that you should not use them. I haven't used mine in , maybe 8 years.

PleasureBay · Post by **PleasureBay** » Wed Sep 19, 2018 5:36 pm

I have a 13'6" traditional style whaler and when trying to find a propeller for highest speed I experienced the same effect. When the hull reached a certain speed it road up on the center section and any movement port or starboard would cause it to chine in. I have also raced boats for over 30 years. When you push the boat fast enough it will ride up on the center section and lose stability.

richcatch22 · Post by **richcatch22** » Thu Sep 20, 2018 4:53 pm

You have to distinguish between normal operation, in all sea condition, versus abnormal behavior. I cruise all day at 25 knots in all seas. At higher speeds the chine walk is more noticeable, but normal and to be expected. At higher speeds keep the tabs up and try in different seas to get used to normal behavior. Tabs down will make it worse at the higher speeds and the bow comes down. Hull was designed for 18-22 knots

Bobjr1261 · Post by **Bobjr1261** » Sun Oct 07, 2018 7:34 pm

Follow up, today I did not use the tabs. 3 spike on board, 3/4 tank of fuel and approx. 35 gallons of water. WOT no chine walk or squatting! 30 mph Seems the tabs were the issue. Thanks for all of the great input. Feel much better knowing this.