Association Forum - trailers & keels

Assn Members Area · Join

Home.

Association Forum

Ships Store

Cruising

Racing

Technical Tips

Photo Gallery - New

Boat Search - Updated

Manuals & Brochures

Swap Meet

Links

Officer Flag Line & Staff

Bylaws & Constitution

Members Area

Join the Association

Notice:
The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.

Association Forum

Username:	Password:
Save Password
Forgot your Password?

All Forums

Catalina/Capri 25/250 Sailor's Forums

Capri 25 Specific Forum

trailers & keels

New Topic

Topic Locked

Printer Friendly

Author

Topic

joemireur
1st Mate

Member Avatar

USA
33 Posts

Initially Posted - 12/01/2008 : 22:05:05

As I walk around looking at other boats on trailers, their keels ALL seem to be resting on the trailer. It seems to be true for Capri 25's and any other boat on a trailer in my marina. My question is, is it better for the boat to have some of the keel on the trailer? Spirit is supported by a pair of pads and a U shaped, padded 2x12. The keel hangs free. The PO used this trailer for winter storage for many years. I have used it since I got the boat last April. The boat stays on the trailer except when its in the water, launching with a crane. Any thoughts, opinions or well thought-out ideas?

"Spirit" '82 Capri 25 #303

Edited by - on

joearcht
Navigator

Members Avatar

USA
241 Posts

Response Posted - 12/02/2008 : 07:28:20

I have no special knowledge on this subject save a college physics course, but this is the way I analyze the question. The load on the keel bolts is not appreciably different when hanging in air or hanging in the water since the keel has no buoyancy to speak of and gravity is a constant. What is different is the loading on the hull.
In the water the weight of the boat is pretty much equally spread over the surface area of the hull below the water line. On dry land, the weight of the boat is concentrated on the pads supporting the hull. Being that this is a "lightweight" boat I would not presume that alot of material was devoted to providing support on pads, thus I think the more evenly you distribute the load on land the better the boat will stand up to the load over time. My boat is supported in its trailer by 4 pads located close to the bulkheads int he boat and the keel. Of course I think it is mandatory to support the keel on a trailer which is not only subjected to gravity loads but also dynamic loading from traveling over the road. With that said, I think it makes sense to pickup some of the load on the keel, but obviously don't over do it. Ideally I'd say support the boat weight on the pads then relieve the keel of its 900 lbs of load only, thus neutralizing the keel bolt load on the hull. Now, how you do this in reality, your guess is as good as mine.

Edited by - on

GaryB
Master Marine Consultant

Members Avatar

USA
4304 Posts

Response Posted - 12/02/2008 : 10:30:36

As Joe suggests above when traveling on the highway the load on a free hanging keel could be tremendous if traveling over a bumpy road.

Walk around a boat yard and you'll notice all the boats supported by stands have the keel resting on a board with the stands snugged up against the bottom of the boat.

From what others have mentioned on this site, Catalina suggests a 60%/40% loading for the C25. I'm not sure if that would apply to the CP25. I've heard other ratios mentioned too. Others have mentioned the keel should handle most of the load with the pads/bunks tight enough to keep the boat from falling off the trailer.

Best advice might be to call Catalina.

Edited by - GaryB on 12/02/2008 10:33:18

joemireur
1st Mate

Members Avatar

USA
33 Posts

Response Posted - 12/02/2008 : 22:39:08

Walking around the yard is how I learned I am the only guy with a free hanging keel. I agree though, it seems unwise to leave it free hanging and particularly so when traveling. And the boat spends most of its time on the trailer, more now than when the PO had it, so - I vill make zee changes und distribute the weight a little better. I don't know how I would be able to tell where I have the 60 and where I have the 40 percent, but I think I'll shoot for having "some" (40%) of the weight resting on the keel.

As to how, that will be a long story. Currently under the keel is a large piece of angle iron welded in place to form a vee under the keel. The keel doesn't come near touching it. Maybe a 2 x 6 would fit just right. I'll check and report back to yall.

As usual, the more I hang out reading what all you guys have to say, the smarter I get!

Thanks!
Joe

Edited by - on

Ericson33
Admiral

Members Avatar

USA
892 Posts

Response Posted - 12/02/2008 : 23:03:53

Joe, I have a trailer that sounds close to yours in your discription. I have a long board in the front of the trailer that extends from port to starboard. I have to adjustable pads in the rear of the trailer that support the hull. I also have a steel v shaped keel support that is under the trailer. I was told that the keel needs to be supported between the axles. I cut a piece of carpet and glued it to the steel rail, I think I used a commercial glue or caulk. My front support is right in line with the side stays, right in line with the forward bulkheads, the rear pads are under the rear bulkheads. The support runs thru the hull up thru the deck. The keel is supported by the v-pad, and you can adjust the rear pad heights by tounge weight. You have to be carefull adjusting the rear pads as they will go right thru the hull and fast. I would suggest chalking the tires witht he trailer attached to you truck, get some adjustable pads and adjust them to the height of the hull, then start dropping each pad in small amounts to float the boat down onto the v-support. The supports on our trailer are just 1/2" holes with bolts threw them to lock in @ 1" steps. If you have the crain option this would be my first try. suport the boat by the strap and then make the adjustments to your trailer.

We float our boat onto the trailer, sometimes it take a couple of times to get the boat right on the trailer, I have no forward support to attach the front of the boat to the trailer, I did make a winch tower, but it still has not been installed.

Good luck and feel free to ask as many questions, thats why we are here.

Edited by - on

joearcht
Navigator

Members Avatar

USA
241 Posts

Response Posted - 12/03/2008 : 07:30:22

I just remembered that I studied my trailer and took pictures for another thread in this forum a while back. I just emailed the pictures to the webmaster and requested that he put them in the Gallery. Trailer needs some repairs, but the main thing to notice is that the keep support on my trailer is "bowed" from the keel load. I'm sure it wasn't designed that way, but put under pretty good loading at some point in the boats history.
I plan to straighten it some day and I guess then I'll try to solve the load balancing issue. Since I leave my boat in the water all year, I really only need the trailer for maintenance and fixing the trailer is low low priority.

Edited by - on

joearcht
Navigator

Members Avatar

USA
241 Posts

Response Posted - 12/03/2008 : 11:29:33

Here are the links to the pics I am told:

http://www.catalina-capri-25s.org/Gallery/Images/Capri/capri-trailerbrakes_2836_1.JPG
http://www.catalina-capri-25s.org/Gallery/Images/Capri/capri-trailerbrakes_2838_2.JPG
http://www.catalina-capri-25s.org/Gallery/Images/Capri/capri-trailerbrakes_2839_3.JPG

Edited by - on

GaryB
Master Marine Consultant

Members Avatar

USA
4304 Posts

Response Posted - 12/03/2008 : 19:57:54

I've always thought the 60/40 meant that 60% of the weight was on the keel and 40% on the hull. I thought this because others have stated that the pads/bunks are more to keep the boat from falling off the trailer than for supporting the weight of the boat.

Maybe someone with more knowledge on this can chime in.

BTW, if you figure out how to determine how much weight is supported by the pads/bunks let me know because I've been trying to figure that out myself.

Edited by - on

joearcht
Navigator

Members Avatar

USA
241 Posts

Response Posted - 12/04/2008 : 07:31:53

I found the paragraph below on the "Jowi" website. They are manufacturers of boat cradles with a fair amount of experiance. I think this supports the idea that the keel should take the majority of the loading.

"Keels can generally support up to 95% of a boat's displacement. The sides and bottoms of most modern laminated hulls should never be required to accept concentrated loads, i.e. a large amount of weight on a few pads. If possible, supporting means used against the hull should be located at bulkheads and/or stringers. Never store a boat with the mast stepped unless the masthead is secured to the ground to prevent the boat from tipping. The side area of a mast is more than sufficient to turn a boat over in high winds."

Edited by - on

joemireur
1st Mate

Members Avatar

USA
33 Posts

Response Posted - 12/04/2008 : 20:32:28

"Good luck and feel free to ask as many questions, thats why we are here."

Except for Dave Bristle. I read in another thread that he's here to get a clue. I still get a kick out of that.

Thanks to all for your input. I don't know whether I've been lucky or the boat is just stronger than many folks think, and I guess it doesn't matter. At any rate, my boat has not <u>yet</u> (a little operative lingo there) been damaged by the supports. But I can see that that is not the same as "never will be damaged". So, it goes on my project list. New wood and rubber bumpers to bang into with keel. And to do something to allow the keel to support the weight of the boat. I'm gonna shoot for supporting 80 to 90 percent or so. If I miss those figures I just won't tell y'all and you won't know. In the unlikely event I figure how to actually tell how much weight is on the keel, I'll pass it on. I have access to a crane, so with the boat in the air, I plan to 1. drop the rear pads way down 2. ease the boat down onto the front pad 3. continue down until the keel is supported, and maybe with a yardstick, measure how much the fender drops as ALL the weight of the boat is divided between front pads and keel 4. pick back up until about 20 percent of that distance is recovered and then raise the rear pads up to the hull. 5. take pictures and retire to write stuff in the forum. And read stuff too.

McKillip: Mine is a Magnum trailer. Yours too?

Edited by - on

Topic

New Topic

Topic Locked

Printer Friendly

Jump To:

Association Forum

Notice: The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.