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Author Topic:   Keel Rollers for Bunk Trailer
RFK posted 08-12-2000 12:21 PM ET (US)   Profile for RFK   Send Email to RFK  
I read your article on trailers for BWs, Jim. I won't go into to the arguement I had with the dealer where I bought my boat, but suffice to say I am using a drive-on bunk trailer. An Eagle Spirit.

Can I add keel rollers to this trailer? If so, where could I get them?

bigz posted 08-12-2000 02:59 PM ET (US)     Profile for bigz    
Sorry RFK don't remember what Whale are your transporting?

I looked up your trailer --- well the major headache you have only 2 fixed bunks --- appreciate before I make a suggestion or state some options let us know the Whaler your hauling, that I am correct this is a single axle, that has a semi- v frame with a couple of short cross member just aft of the bow post --- you have a cross member for the forward bunk support, a cross member over the axle and of course the rear frame cross member --- correct me where I am wrong then can give you some options --- always more ways than one to skin a cat yeah know --- regardless of what some folks may think ---


jimh posted 08-13-2000 08:37 AM ET (US)     Profile for jimh  Send Email to jimh     

It is hard to find a new trailer that is set up with a combination of keel rollers and bunks.

Eagle is a nice trailer--they are made just a few miles from me in SE Michigan and many new boats are delivered on them in this area.

And the bunk/float-on style does work; there are a zillion people launching and recovering boats (including Whalers) from them everyday.

One argument that the bunk trailer fans make against the keel-rollers is that the little steel shafts of the rollers can't carry the weight load of the boat and they deflect and bow. There might be some truth to that, but if you use double sets of rollers at each crossmember (and you have more than one or two crossmembers) you will distribute the load to more rollers at a time.

One thing I like about some bunk trailers (like the Eagle) is the bunks being all welded in place. That makes a very stable cradle for the boat; you don't have to worry about an adjustable bunk shifting as a result of a big jolt on the highway.

You can add keel rollers to the bunk trailer, assuming you have enough cross members, especially the most important one, a good crossmember right at the rear of the trailer.

You can buy the poly-rollers, galvanized brackets, and SS axle pins, and bolt on the brackets. I would look carefully at the crossmembers before drilling big holes in them to mount the brackets. You'll be weakening them right at the point of maximum stress. It would be better if you could bolt the brackets for the rollers onto the crossmembers without having to drill through the crossmembers. It may be possible to use long bolts and clamp two brackets back-to-back on either side of a crossmember, sandwiching the crossmember between them.

It would also be best if you mount the brackets in such a way that the bolt that passes above the trailer frame is contained in a single small hole in each roller bracket, not a slot. That way you will have locked the bracket in position and it cannot shift downward. Of course, it might require a very good eye and some careful measurements to position that hole just right, but there is room for some adjustment.

If the hole sets the roller too low, you could place some shims between the upper bolts and the trailer frame to raise it.

If the hole sets the roller to high, you can enlongate the hole slightly to lower it.

Or you could sacrifice one bracket pair as test templates, and drill a series of holes in them at slightly staggered heights, fit each roller pair to the trailer using the test template to determine optimum height,
and, when you have the perfect fit, use the template brackets as guides to drill a single set of holes in the actual brackets!

Doing it that way, and maybe using some small shims under the bolts, you should be able to create a perfectly set up roller height.

You want the rollers to pick up the majority of the boat's weight. That will make for the best launching and loading.

--Jim Hebert

bigz posted 08-13-2000 11:09 AM ET (US)     Profile for bigz    

Here is another idea based on the Eagle Spirit's configuration or at least the way I understand it.

RFK you are confined to where the bunks sit on the Whaler's hull --- these are fixed and actually are a structural member of the trailer frame (welded)! On the small single axle I don't know if there is a cross member over the axle but the fore and rear cross members are cradled so that the keel has no support what so ever! Boat is suspended on these outer bunks!

Jim's idea of installing a rear keel roller is great except you need more than one point support since the current bunks are fixed and should just offer lateral stability not support, one needs at least 3 points spaced out to allow for proper keel roller support, even on a 13.

Since RFK your stuck with the fixed bunks my simple idea would be to add a pair of keel support bunks mounted and angled as close to the keel as possible offering a nice solid cradle along the whole length and a rear mounted keel roller. (Eagle offers these keel bunks or fact similar on their 2 axle trailers)

The keel support bunk heights will need to be adjusted so the outboard fixed bunks just barely touch the hull offering only lateral stability, and the keel bunks make total contact with the hull on either side of the keel. These can be purchased from any good trailer supply and also mail ordered.

They must however should be positioned no more than about 2" - 4" off the keel and a keel roller positioned outboard of the rear cross frame as Jim described --- BW lays up the keel very heavy about 4-6" along on both sides it . This is the area necessary for supports to make contact --- . The cross members on the Eagle's cradled frame are designed for this application -- why re-invent the wheel. Then add a bow take up roller so that when the boat is cranked up the last inch or two tight it will pull it nice and snug on the keel support bunks and rear roller. --- Make sure there is no more than an a few inches of the transom over the rear frame cross member and it is solidly supported by the keel roller and bunks . Spray a little silicone on the bunks and you'll launch and retrieve like a rocket sled --- use transom straps and a good gunwale strap with support so your not crushing the rub rail ( just helps stabilize the boat laterally), also use a single ratchet type hold down from the bow eye to the trailer frame ( just mount an eye bolt below the trailer post for attachment)

Anyway them's my thoughts and believe the most economical and simple way to accomplish the primary goal of keel and transom support, given the trailer design --- everyone has their own ideas and I have more than enough for anyone and everything --- chuckle Tom

Clark Roberts posted 08-13-2000 12:57 PM ET (US)     Profile for Clark Roberts  Send Email to Clark Roberts     
RFK, I have a new "Load Master" custom drive-on 100% bunk trailer for my 21 Revenge. I have what I call a "pick-up" roller positioned forward so that the last few turns of the winch bring the keel up onto this roller and the front end raises up about 1"... this unloads the canard (short forward wing bunks) and puts load onto the main bunks where they contact the transom. Thus, when winched into trailering position, the hull has 3 point support (forward keel on "pick-up" roller and at either side at the transom.... the strongest part of the hull)! This works well and it's very easy on and off... and loading onto trailer is "first time every time".. boat can't go on wrong! Best of both worlds as far as I'm concerned! Try it, you'll like it!! BTW there are as many opinions on this subject as there are Whalers... Happy Whalin'.... Clark.. Spruce Creek Navy
lhg posted 08-13-2000 11:13 PM ET (US)     Profile for lhg    
Jim, regarding your note on black keel rollers bending under load, this can be true and is why I swear by the Stoltz polyurethane rollers instead. They have a steel sleeve in them, and are probably four times as strong in bending resistance as those black rubber rollers, which do not have the steel imbedded in them.

Regarding drilling any trailer frame component, always try to drill on the vertical center line of the member. Under most conditions this will not weaken the section at all, as there are no compression or tension stresses at this point of a beam. (top of beam is in compression, and bottom is in tension) Actually, this is the only point where it is safe to drill a frame beam in mid span.

RFK posted 08-14-2000 08:07 AM ET (US)     Profile for RFK  Send Email to RFK     
Thank you all very much. I am going to look into several of the ideas.

On one point that Jim made. The dealer delivered the boat, a 16SL, on a Calkins bunk trailer. We had an arguement over it because it didn't have center keel rollers. BW supported the dealer. I didn't feel comfortable with the trailer because the bunks were adjustable, not fixed. I went through one season with it, then ordered the Eagle. In fact, it does seem to give good support and is stable. The idea of a bow loading roller would seem to be a good adaptation.

Incidently, I needed to re-pack my trailer hubs and I decided to go to Liqua-Lube's synthetic lubricant. It may be my imagination, but the trailer pulls great. I caught it at the right time because the races(sp) were scored and I avoided trouble.

Again, thank you for the advice.

Clark Roberts posted 08-14-2000 09:03 AM ET (US)     Profile for Clark Roberts  Send Email to Clark Roberts     
Some thoughts on trailering: Any trailer type/set-up may be ok on a smoothe level road with no traffic, heck, a flat-bed might work! Try to imagine the worst case condition that might be encountered, like emergency maneuver and off road down the ditch bouncing over culverts.... ???? The trailer can actually "jack hammer" the boat's hull to pieces and even unhitch the coupler from the ball (I have had this happen to me on a bad railroad crossing.. luckily no damage but scarry as hell). Each should set up his towing package (includes hitch, safety chains, boat straps...hitch ball properly adjusted to coupler.. etc.etc.) to worse case conditions... never even think of trailering without boat strapped to trailer even for a block.. A friend of mine had his Montauk pass him, sliding down the highway when he swerved to avoid something.... right, no straps! Minor hull damage but the liability was that he might have killed someone... Happy Trailering..... Clark... The Old Man and The Sea...

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