Reply
 
Thread Tools Display Modes
 
Old 09-18-2015, 05:33 PM   #1
Veteran Member
 
Legend's Avatar
 
City: Annapolis
Country: USA
Vessel Name: Legend
Vessel Model: Halvorsen 39 Hard Top Express
Join Date: Sep 2015
Posts: 79
Semi displacement and quartering seas

There seems to be only one handling characteristic of my Halvorsen that I dislike. It is when I find myself in quartering seas. They lift up a corner of the transom and with the semi displacement deep forefoot she will catch an upcoming wave at an angle creating bow steer. This makes her roll a bit and can be unnerving for passengers. My only solution to that other than a new course is to raise the bow as high as I can to try and avoid bow steer. Any suggestions from other semi displacement boat owners?
__________________
Advertisement

Legend is offline   Reply With Quote
Old 09-18-2015, 05:51 PM   #2
Guru
 
caltexflanc's Avatar
 
City: North Carolina for now
Country: USA
Vessel Name: Small Incentive
Vessel Model: Boston Whaler 130 Sport
Join Date: Aug 2011
Posts: 3,797
You don't want to tab it up in a following sea as that will push you around even more. Adjusting the throttles to match the seas is the best way to mitigate the effect. The "roll" you are experiencing is typically more of a combination of pitch and yaw; it is indeed an uncomfortable motion.
__________________

__________________
George

"There's the Right Way, the Wrong Way, and what some guy says he's gotten away with"
caltexflanc is online now   Reply With Quote
Old 09-18-2015, 05:59 PM   #3
Veteran Member
 
Legend's Avatar
 
City: Annapolis
Country: USA
Vessel Name: Legend
Vessel Model: Halvorsen 39 Hard Top Express
Join Date: Sep 2015
Posts: 79
Quote:
Originally Posted by caltexflanc View Post
You don't want to tab it up in a following sea as that will push you around even more. Adjusting the throttles to match the seas is the best way to mitigate the effect. The "roll" you are experiencing is typically more of a combination of pitch and yaw; it is indeed an uncomfortable motion.
Thank you. I will try that approach.
Legend is offline   Reply With Quote
Old 09-18-2015, 06:02 PM   #4
Guru
 
caltexflanc's Avatar
 
City: North Carolina for now
Country: USA
Vessel Name: Small Incentive
Vessel Model: Boston Whaler 130 Sport
Join Date: Aug 2011
Posts: 3,797
You're welcome. Look at the big fat butt on that Hatt; I feel your pain. And remember I said "mitigate" not "cure"!
__________________
George

"There's the Right Way, the Wrong Way, and what some guy says he's gotten away with"
caltexflanc is online now   Reply With Quote
Old 09-18-2015, 08:33 PM   #5
TF Site Team
 
dwhatty's Avatar
 
City: Home Port: Buck's Harbor, Maine
Country: USA
Vessel Name: "Emily Anne"
Vessel Model: 2001 Island Gypsy 32 Europa (Hull #146)
Join Date: Sep 2008
Posts: 2,733
Been there, done that in our Halvorsen. Can be truly scary.
__________________
David Hawkins
Deer Isle, Maine
dwhatty is online now   Reply With Quote
Old 09-18-2015, 09:03 PM   #6
Master and Commander
 
markpierce's Avatar
 
City: Vallejo CA
Country: USA
Vessel Name: Carquinez Coot
Vessel Model: 2011 Seahorse Marine Coot hull #6
Join Date: Sep 2010
Posts: 10,262
This occurs with full-displacement boats too. Experienced it a lot on sailboats. Steering with a tiller provided instant tactile information to apply quick rudder adjustment to minimize effect, although we did experience some knockdowns carrying a spinnaker. With wheel steering, making timely rudder adjustments is more challenging but can be done.
__________________
Kar-KEEN-ez Koot
markpierce is online now   Reply With Quote
Old 09-18-2015, 09:34 PM   #7
Guru
 
Nomad Willy's Avatar
 
City: Concrete Washington State
Country: USA
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 13,712
Nothing like a big rudder.

Good fore and aft weight ballance will help too. I have two 50 gal water tanks far aft in my 30' boat and I like to have them fairly full especially when I'm on following seas.

Mark is on the mark as FD boats have some trouble w following seas too .... just far less.
__________________
Eric

North Western Washington State USA
Nomad Willy is offline   Reply With Quote
Old 09-18-2015, 09:48 PM   #8
Guru
 
Moonstruck's Avatar
 
City: Hailing Port: Charleston, SC
Country: USA
Vessel Name: Moonstruck
Vessel Model: Sabre 42 Hardtop Express
Join Date: Nov 2008
Posts: 7,848
Nathan, you got spoiled running your Sabre. The V hull tracks and plenty of power to push you through. The flatter areas of the Halversen's bottom near the stern coupled with the flat transom and small rudders means trouble in a quartering sea. Add to that the steep, close chop of the Chesapeake, and it can get quite uncomfortable.

Like George said take the tabs off to sink the stern. Regulate the speed for the most comfortable ride. This should provide some stability.
__________________
Don on Moonstruck
Sabre 42 Hardtop Express & Blackfin 25 CC
When cruising life is simpler, but on a grander scale (author unknown)
http://moonstruckblog.wordpress.com/
Moonstruck is offline   Reply With Quote
Old 09-18-2015, 09:50 PM   #9
Guru
 
BandB's Avatar
 
City: Fort Lauderdale
Country: USA
Join Date: Jan 2014
Posts: 13,150
Quote:
Originally Posted by caltexflanc View Post
You don't want to tab it up in a following sea as that will push you around even more. Adjusting the throttles to match the seas is the best way to mitigate the effect. The "roll" you are experiencing is typically more of a combination of pitch and yaw; it is indeed an uncomfortable motion.
The human tendency is that when things get rough to go very slow. Yet, this is a great example of situations where a bit more speed is far more comfortable. It takes a lot of time to learn all the characteristics of a boat in as many different sea conditions as possible.
BandB is online now   Reply With Quote
Old 09-18-2015, 11:04 PM   #10
Al
Guru
 
Al's Avatar
 
City: ketchikan, Alaska
Country: usa
Vessel Name: 'SLO'~BELLE
Vessel Model: 1978 Marben-27' Flybridge Trawler Pilothouse Pocket Cruiser[
Join Date: Apr 2012
Posts: 1,690
BandB has it.

We endured a following sea voyage early this week. While I didn't slow down to meet conditions as the boat was doing well other than the slewing about which being as slow as we are would not have resulted in much more that more time with the issue, During these struggles, a slightly larger simi-dis boat with sufficient power was running on step. Unlike a lightly constructed 'Go Fast' hull, rather a heavy built boat, was not having near the challenge we were under. It was with admiration watching this boat eat up the following seas.

During the past year I have been increasing the amount of lead ballast in our boat. The last installment was an additional 104# in two ingots. The beauty of these ingots is the ability to shift the weight around the bilge. This has allowed us to decrease the slewing effect. We now have a total of 1250# of lead in the bilge plus 400# of additional engine/gear weight with a recent engine replacement. In short, we have a completely different boat from what we bought.

Al-Ketchikan
Al is offline   Reply With Quote
Old 09-18-2015, 11:18 PM   #11
Guru
 
Nomad Willy's Avatar
 
City: Concrete Washington State
Country: USA
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 13,712
Al I hope your lead is secure as a big heavy pice of lead slamming about in a boat in conditions where it hard to stand up in is not good.
__________________
Eric

North Western Washington State USA
Nomad Willy is offline   Reply With Quote
Old 09-19-2015, 12:48 AM   #12
Guru
 
Scary's Avatar
 
City: Walnut Grove Ca
Country: USA
Vessel Name: Cary'D Away
Vessel Model: Hatteras 48 LRC
Join Date: Apr 2012
Posts: 884
Tendency to broach

This what you are describing. This can get you in trouble as the seas get large enough to cause the boat to surf. With a fast powerful boat surfing can be fun, with a slower boat it can be uncomfortable and potentially dangerous. Small rudders and hard chines make it more difficult to keep your boat tracking straight. If you have trim tabs don't run them in the down position, this make it worse, The 4788 bayliner has a warning label at the tab controls against this. if you can run at the speed of the waves this will help, keep your boat on the back side of the waves as much as possible. This uses more fuel but provides better tracking. If you can, try and run as square to the waves as possible, this may mean holding a course other than rumb line. Be careful not to end up having to finish your approach with beam seas. This condition is common on south runs on the west coast. What I do is take advantage of the smaller waves to move the boat back towards my track, sort of a controlled s shaped course ridding the back of the larger waves and working toward my track on the smaller ones. You will actively have to drive your boat in these conditions. A good Auto Pilot will get you there but it won't be pretty or comfortable. I've been on boats that Yaw as much as 40 deg. I've also been on boats like 48 lrc that track like there on rails.
Scary is offline   Reply With Quote
Old 09-19-2015, 01:42 AM   #13
Guru
 
BandB's Avatar
 
City: Fort Lauderdale
Country: USA
Join Date: Jan 2014
Posts: 13,150
Tack like a sailboat if you can't find a comfortable speed. Lengthens the trip but makes it more comfortable.
BandB is online now   Reply With Quote
Old 09-19-2015, 01:57 AM   #14
Al
Guru
 
Al's Avatar
 
City: ketchikan, Alaska
Country: usa
Vessel Name: 'SLO'~BELLE
Vessel Model: 1978 Marben-27' Flybridge Trawler Pilothouse Pocket Cruiser[
Join Date: Apr 2012
Posts: 1,690
Scary, You have just described our voyage. While speed was not a factor in this case, all of the other identifiers with a displacement hull are confirmed.


Eric- The lead is in ingot form, like gold bars. They are stowed in the keel alleyway on top of the inlayed 1500# of original build secured under a fiberglass floor. These additional ingots are layed end to end two ingots high and are in effect 'jammed' into place requiring a screwdriver tip to jack one up should that be required. Others of the ingots are layed alongside the engine bed and secured with 'Gorilla' tape in both directions. Used the widest width of tape and double taped the parameter of the ingots. Appears to be satisfactory to this point.
Having the ability to move the ingots has allowed me to find a friendly ballasting in terms of ending the severe 'hobby horse bucking into seas and for sure, having a most comfortable minimum angle in beam seas allowing the boat to remain on even keel in those 'almost' beam sea conditions.

Don't I have a memories of you saying you have 3000# total of dedicated ballast in your boat? If that is correct, then my 2700# of dedicated ballast is close.
From the first post made regarding the horrid sea actions of this boat upon first exposure to our SE waters to now has been a story. Now Eric, the bitching about slewing in a quarter following sea represents the only quadrant of discomfort while underway, all others are so much improved.
regards,
Al-Ketchikan
Al is offline   Reply With Quote
Old 09-19-2015, 05:40 AM   #15
Guru
 
Rustybarge's Avatar
 
City: I need a bigger boat!
Country: Ireland
Vessel Model: Cheetah 25' Powercat.
Join Date: Aug 2014
Posts: 925
Quote:
Originally Posted by Scary View Post
This what you are describing. This can get you in trouble as the seas get large enough to cause the boat to surf. With a fast powerful boat surfing can be fun, with a slower boat it can be uncomfortable and potentially dangerous. Small rudders and hard chines make it more difficult to keep your boat tracking straight. If you have trim tabs don't run them in the down position, this make it worse, The 4788 bayliner has a warning label at the tab controls against this. if you can run at the speed of the waves this will help, keep your boat on the back side of the waves as much as possible. This uses more fuel but provides better tracking. If you can, try and run as square to the waves as possible, this may mean holding a course other than rumb line. Be careful not to end up having to finish your approach with beam seas. This condition is common on south runs on the west coast. What I do is take advantage of the smaller waves to move the boat back towards my track, sort of a controlled s shaped course ridding the back of the larger waves and working toward my track on the smaller ones. You will actively have to drive your boat in these conditions. A good Auto Pilot will get you there but it won't be pretty or comfortable. I've been on boats that Yaw as much as 40 deg. I've also been on boats like 48 lrc that track like there on rails.
Very interesting; why is the Hatt so good at tracking....what's different about the transom?

I notice there's some deadrise, does this help?





__________________
Peter.
Rustybarge is offline   Reply With Quote
Old 09-19-2015, 08:11 AM   #16
Guru
 
caltexflanc's Avatar
 
City: North Carolina for now
Country: USA
Vessel Name: Small Incentive
Vessel Model: Boston Whaler 130 Sport
Join Date: Aug 2011
Posts: 3,797
Quote:
If you have trim tabs don't run them in the down position, this make it worse, The 4788 bayliner has a warning label at the tab controls against this.
Thanks for the important clarification. So does the Hatteras. I think my post may have been confusing, by "tab it up" I meant using tabs to raise the stern like you do when planing. The tabs themselves need to be fully up. When they are down, thats more surface to get pushed around and, more dangerously, guiding the bow down into the seas.

As for tacking, that's fine in open water and helps some. The most pucker-inducing situations are coming into an inlet in mediocre conditions. In poor or bad conditions, just don't do it.

FD boats with canoe sterns do much better in following seas. Some of the issues in quartering is the very deep keel something like a sail boat has will cause the boat to track more determinedly in the direction it gets pointed after being moved by the sea, requiring vigourous helmsmanship. The Hatteras (ours in this case) also has a modestly deep keel, and that's when having the ability to go faster is a real bonus.
__________________
George

"There's the Right Way, the Wrong Way, and what some guy says he's gotten away with"
caltexflanc is online now   Reply With Quote
Old 09-19-2015, 09:46 AM   #17
Guru
 
Codger2's Avatar
 
City: San Diego
Country: US
Vessel Name: "Sandpiper"
Vessel Model: 2006 42' Ocean Alexander Sedan
Join Date: Oct 2007
Posts: 5,420
Quote:
Originally Posted by caltexflanc View Post
"You don't want to tab it up in a following sea as that will push you around even more." .
George, I've been thinking about that remark ever since you posted it. I've interpreted it to mean that you never want to trim the trim tabs to a "bow up" configuration in a following sea." I've been taught just the opposite! By trimming to "bow up", you minimize the boat trying to bury its bow when on the front side of a wave. Of course, manipulating the throttles to match the sea conditions is a given. I wish more on TF would add their 2 cents to this question.
__________________
Codger2

My passion for improving my boat(s) exceeds my desire to constantly cruise them.
Codger2 is offline   Reply With Quote
Old 09-19-2015, 09:57 AM   #18
Guru
 
BandB's Avatar
 
City: Fort Lauderdale
Country: USA
Join Date: Jan 2014
Posts: 13,150
Quote:
Originally Posted by Codger2 View Post
George, I've been thinking about that remark ever since you posted it. I've interpreted it to mean that you never want to trim the trim tabs to a "bow up" configuration in a following sea." I've been taught just the opposite! By trimming to "bow up", you minimize the boat trying to bury its bow when on the front side of a wave. Of course, manipulating the throttles to match the sea conditions is a given. I wish more on TF would add their 2 cents to this question.
George clarified and meant exactly what you say. My understanding is the same. Put another way, "Don't bury the bow."

When you're "practicing" that's something else to work on is the proper and best use of your trim tabs. "Practicing", you ask. Yes. Find space where you won't put yourself in harm's way as you would in an inlet. Don't learn when you have no way out. When you're out cruising, take time occasionally in different conditions to see how your boat behaves and how you can handle it. When we were first learning we were put through hours of practice in the gulf in rough conditions and trying with the waves coming from every possible different direction. That's where we learned the way to match speed to conditions, the impact of the various levels of tab. By the time our "teacher" said to let's go in, we knew what we needed to do for the inlet. Not only had our knowledge and skill changed, our instincts had. Our first and most natural thoughts were different.

As Caltex states too if you can't find a safe means of handling the inlet with conditions and your specific boat, then wait or find somewhere else or somehow rethink things. Perhaps ask the CG for suggestions or options, check forecasts. If opportunity to observe others presents itself then do so. We had a Gray's Harbor for Dummies course just observing all the charter fishing boats. It was our first time ever to see 10'+ swells, but they faced them regularly.

Also, give yourself all the room for error you possibly can so if you do get pushed off track you have the time and space to recover.
BandB is online now   Reply With Quote
Old 09-19-2015, 10:41 AM   #19
Guru
 
Nomad Willy's Avatar
 
City: Concrete Washington State
Country: USA
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 13,712
Can anyone think of a positive reason to use trim tabs in following seas or while running an inlet?
In such conditions I'd raise the tabs and forget about them. But I've never had tabs so I may be missing something.

There's talk of "why is the Hatt so good at tracking". Is it?
Any twin will be able to power steer and drag steer (w one prop at idle speed).
A high LB ratio may help.
The drag of a deeply submerged transom will help.

But why would a Hatt track better than the average boat of her type?
Not much keel.
Not much deadrise aft.
Small rudders.

Is lots of beam carried far fwd? As in wide chines fwd?
She has a very nice forefoot much like a FD hull. Could this be an advantage? I don't see it myself but for a SD/Cruiser hull having a sharp forefoot and the rudders well aft would definitely help tracking most of the time.

Codger I fully agree re bow up.
__________________
Eric

North Western Washington State USA
Nomad Willy is offline   Reply With Quote
Old 09-19-2015, 10:45 AM   #20
Guru
 
caltexflanc's Avatar
 
City: North Carolina for now
Country: USA
Vessel Name: Small Incentive
Vessel Model: Boston Whaler 130 Sport
Join Date: Aug 2011
Posts: 3,797
Quote:
Originally Posted by manyboats View Post
Can anyone think of a positive reason to use trim tabs in following seas or while running an inlet?
In such conditions I'd raise the tabs and forget about them. But I've never had tabs so I may be missing something.
Nope, missing nothing, you are exactly right . That's why boat manufacturers like Hatteras and Bayliner mentioned above actually put warning labels next to the tab controls.
__________________

__________________
George

"There's the Right Way, the Wrong Way, and what some guy says he's gotten away with"
caltexflanc is online now   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





All times are GMT -5. The time now is 05:27 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012