More V - C-series

Ask questions before buying our plans or request a new design. Anybody can post here
Fuzz
* Bateau Builder - Expert *
* Bateau Builder - Expert *
Posts: 8945
Joined: Tue Aug 02, 2011 4:23 am
Location: Kasilof, Alaska

Re: More V - C-series

Post by Fuzz »

bklake wrote: Wed Sep 20, 2023 9:30 am I'm going through a deadrise education the hard way right now. I got a new boat with a 15deg deadrise and it slams more than my old boat with a 22deg deadrise. I am learning how to control the slamming better. And, it is controllable.

In general, the new boat rocks on the water a lot less. Very true that a deep vee will rock. I never liked the rocking motion. When moored or tied up with other boats, my old boat rolled a lot more than others. The new boat slams a lot more so it is true that shallow vee slams more.

I have slammed my deep vee very hard, teeth breaking hard, before. A combination of doing everything wrong at the worst possible time. On the new boat. I have so far, soften some sure slams in the shallower vee by doing everything right at the right time. Conclusion: Vee is not a guarantee of a smoother ride.

I have seen and read reviews on shallow vee boats that are known for their smooth ride and stability. I think it has to do with how the bow cuts the waves and a few other factors. I don't care what hull you have, there is no boat that can go smoothly through chop at 35kts and not slam. Slamming is 99% controlled by the knucklehead at the helm. I was on the USS Roosevelt in a storm with waves breaking over the bow. It was slamming. Man has not yet made a boat that can defeat Mother Nature. You can dance a beautiful dance with her but you better not square off with her.

Don't get mired in the vee at the transom. Factor everything in. Most importantly, get a ride on a boat that you are interested in, in the conditions you need to evaluate. Some will surprise you. Both ways.
Damn good post!

User avatar
BarraMan
* Bateau Builder - Expert *
* Bateau Builder - Expert *
Posts: 2166
Joined: Tue Dec 11, 2012 3:44 pm
Location: Australia

Re: More V - C-series

Post by BarraMan »

Much also depends on the prevailing sea conditions!

My boat, with its hull shape and 18 degrees of dead-rise at the transom does not slam, even in the worst conditions we have encountered. What is does have a tendency to do, even though its 22' long and with the nose trimmed up as much as possible, is bury its nose into an oncoming wave! :help:

This is the result of the frequency and amplitude of the waves that arise in the relatively shallow Gulf of Carpentaria. This can be countered to some extent by slowing right down but there are times when you just shouldn't be there - as I a ably demonstrated on our last fishing trip.

For those who may have missed the fun on the fishing thread:




TomW1
Very Active Poster
Very Active Poster
Posts: 5859
Joined: Sun Apr 19, 2015 10:57 pm
Location: Bryson City, NC

Re: More V - C-series

Post by TomW1 »

If you look at the study plans the C19 is only 4" shorter than the MG20 but is a 1' wider. It is also higher at the bow and sides. The spray rails on her will also make her dryer. I am not saying the MG20 is a bad boat but why not build a boat that is designed for going offshore? Good luck on your decision.

Tom
Restored Mirror Dinghy, Bought OD18 built by CL, Westlawn School of Yacht Design courses. LT US Navy 1970-1978

Johnston
Frequent Poster
Frequent Poster
Posts: 44
Joined: Wed Dec 23, 2020 4:00 am

Re: More V - C-series

Post by Johnston »

Please understand I am not questioning the seaworthiness of the C - series boats.

What I am questioning is whether the relatively shallow V of the boat makes them uncomfortable in chop/ a head sea; and whether there would be a more comfortable and equally safe option.

I have heard at least one other boat designer comment that whilst a flatter V might be more fuel efficient in a calm sea, the boat gets buffeted around more and that a deeper V prevents the boat from being pushed off course as much so in real world conditions the difference becomes less significant.

In addition, I would think that the deeper the V the stronger the hill bottom for a given weight of material?

I may look more closely at the Abaco 23

joe2700
Very Active Poster
Very Active Poster
Posts: 632
Joined: Fri Nov 25, 2016 3:16 pm
Location: Massachusetts

Re: More V - C-series

Post by joe2700 »

Certainly in a shallow V you need to slow down more in chop/waves to not slam. For comfort and minimizing how much you get tossed around I think weight is also a big factor. A big advantage of most of these designs is that they can be lighter than a production boat. More fuel efficient, faster to plane, easier to trailer but a downside is you probably get tossed around more as you are more on the water than in it.

If running in heavier seas is your goal I'd look for a design that in addition to having a deeper V is heavier or can be purposely built heavier especially on the bottom. I think you will appreciate a heavy boat with a very stiff bottom if that is a main goal.

I have a fast skiff 17 that is very heavy for an FS17 at almost 2000 lbs before crew and has a raised sheer(especially at bow) and almost full length keel. I can't go fast into waves because it is so flat at the back and will slam like crazy. I can be out in pretty heavy seas for a 17' boat at semi displacement speed and feel perfectly safe and not like I'm getting tossed around a ton.

If I were you I'd pick a design with the hull shape and structure you want below the waterline, don't try to mess with that. Change whatever you want within reason above the waterline. Then figure out how to add a bunch of weight from the sole down. Double or triple the fiberglass on both sides of the bottom, thicker plywood for the sole, big lead acid batteries under the console. Stay aware of how much weight you are adding and where it will put the waterline and the scuppers, you may have the raise the sole.

I am very much no an expert, but what you describe makes me think you want heavy so you can just power through some waves.

David 9 boats
New Poster
New Poster
Posts: 4
Joined: Sat Jan 01, 2022 2:13 am
Location: Oregon

Re: More V - C-series

Post by David 9 boats »

Exactly what are "certain conditions" and do you really want to be out there in a 19' boat?

TomW1
Very Active Poster
Very Active Poster
Posts: 5859
Joined: Sun Apr 19, 2015 10:57 pm
Location: Bryson City, NC

Re: More V - C-series

Post by TomW1 »

Johnston can you give us an idea of where you are located and what you are going to be going be using this boat for. We will be better equipped to give you suggestions on which boat plans to look at. What are your normal conditions that you are out in.

Tom
Restored Mirror Dinghy, Bought OD18 built by CL, Westlawn School of Yacht Design courses. LT US Navy 1970-1978

Johnston
Frequent Poster
Frequent Poster
Posts: 44
Joined: Wed Dec 23, 2020 4:00 am

Re: More V - C-series

Post by Johnston »

Boat would be used in Gabon - West Africa. We have a variety of sea conditions/ types of water it is fair to say.
But I don’t want a boat that will be uncomfortable and require going very slow in short wind driven chop.

I read a post somewhere on this forum about a guy with one of the Downeast style boats that he had to slow right down to get home. I believe this is a similar bottom shape to the C-series?

Again I am not questioning the safety of the vessel; just whether there are designs here that would have performed better in these conditions?

CS23 or Abaco 23?

User avatar
BarraMan
* Bateau Builder - Expert *
* Bateau Builder - Expert *
Posts: 2166
Joined: Tue Dec 11, 2012 3:44 pm
Location: Australia

Re: More V - C-series

Post by BarraMan »

Johnston wrote: Sun Sep 24, 2023 12:27 am CS23 or Abaco 23?
I think the only boat here that will meet your requirements is the Carolina Sportsfish in either 23' or 25'. A wave breaker on it would make it even more seaworthy!

The Abaco 23 hull is actually very similar in specs to how my boat (modified Mangusta 20) turned out, and as you can see above you need to be very careful taking that boat out of semi-sheltered waters!

What are regarded as good off-shore boats in this part of the world generally have at least 21 degrees of deadrise at the transom.

pee wee
Very Active Poster
Very Active Poster
Posts: 2306
Joined: Sun May 01, 2011 8:29 am
Location: Georgia

Re: More V - C-series

Post by pee wee »

If you're looking to get a deep V for offshore use, how about going this route (same boat):

viewtopic.php?t=62291

Image

Image
Last edited by pee wee on Mon Sep 25, 2023 9:30 am, edited 1 time in total.
Hank

Post Reply

Who is online

Users browsing this forum: No registered users and 0 guests