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Bluejacket 25.5 (PurDee) Finished

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Last week I declared my 25.5 finished and we managed putting it in the water this weekend.  

 

Friday I took the boat to Crop Production Services and had it weighed.  It was 5900 LBS including the galvanized trailer and full with 29 gallons gas and 34 gallons water.  I get the trailer weighed tomorrow.  I will try to get some performance data together when we are using the boat.  I did notice it was a bit slower than last fall but the boat gained about 300 LBS over the winter.  Wiring plumbing and some more stuff like drawers etc.

 

I do have a question for Tom.  We keep the boat on a boat lift.  Does the transom need to be supported by the bunks, If I do than the boat sits way to far forward on the lift.  The way it sits on the lift now the transom overhangs the bunks a little over one foot and the end around where the fore cabin starts.

 

Egbert

 

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Ideally, the lift bunks should be located directly under the bilge stringers and the transom should also be resting on them. For short durations, this isn't a big concern though over time, a hook will likely develop, if the bunks are inboard of the transom.

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Paul,  Bluejackets have a torsion box bottom structure with longitudinal bulkheads spaced on 7 1/2" centers and are about 10 inches high near the transom so placing bunks under a pair of these is not likely to allow any distortion.  Much stiffer than any stringer system could be.  Actually, that is how it developed when I found that a longitudinal bulkhead/torsion box system could be built lighter and much stronger than a stringer system. 

 

I am more concerned about the long cantilever off the bow beyond the bunks and as the increasing deadrise lifts the bottom off the bunks.  This is usually taken care of on a trailer with support on the forward keel.  What are your thoughts?

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Sorry, wasn't aware of the structural arrangement on this boat, sounds pretty clever. I use a similar setup on racers, though certainly have plenty of longitudinal stringer designs as well.

 

The one picture does seem to show the bunks clear of the bottom in the forward sections, but it's tough to tell, without a better angle. I agree, something on the centerline should be considered. How far back is the first I beam and can a roller be mounted to it? Just guessing at the distance, I think a roller farther forward might be necessary for long duration rides on that lift. Maybe another I beam, welded under the two athwart beams, down the centerline, so you have a place for multiple rollers?

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This stuff is WAAAY outside my experience or knowledge, but I had to look at this thread, because that boat is NIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIICE!

The upside to not getting more juicy photos of some neat thing, is learning a lot about boats, their structures, and how to manage them from two guys who know what's what.

I am very interested, academically, in what comes of this.

And did I mention that is my type of motor boat? Nice work to the two gents involved I penning and realizing her...

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Egbert,

 

I suspect you are aware that I am a bit concerned about the long term support of your beautiful boat.  The forward overhang is something over 10' with no keel support, depending on how much the bottom rises off the bunks.    I do think that the bunks on your lift  may need some inspection .  Perhaps some photos along with a couple measurements would help to clarify things.  The weight increase between the two measurements of 740 Lbs seems excessive.  How confident are you of their accuracy?

 

I don't think that the boat is in any danger but think that some keel support at or even forward of the forward crossbeam might be considered.  Alternatively the existing bunks might be replaced with longer ones so that the boat could be better balanced as well as extend to the transom. 

 

Anyone wanting to see more of this boat should look at post #36 of this thread and Egberts builders blog at:

http://www.flickr.com/photos/58798913@N03/

 

There is also a very nice Bluejacket 28 on post #39.  As the builder of the BJ28 is not identified, I am not 100% certain whose boat it is.

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Tom. 

 

Replacing and extending the bunks is pretty much the only thing I can do with the boat lift. I should be able to make a cross piece to support the keel forward.  I'll try to take some clearer pictures.  

 

I had the trailer weighed today so the total boat weight is 5900 - 1440 = 4460.  This is including 29 gallons gas and 37 gallons water.  The actual boat weight empty is almost 4000 LBS.  Your comment about a "Fat Lady" was very appropriate.  I would think that the scale must be fairly accurate since it is used for commercial purposes selling corn seed and fertilizer.   I don't know the capacity but it is a fairly small truck scale.  

 

I believe that the 28 in post #39 is one in the Northwest.  I think that Henry is going to visit them this summer or fall, he should know more.

 

Egbert

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Thanks Action Tiger,

 

The design is a big part of the boat.  I needed a shallow draft, economical boat that 2 people comfortable can stay on.  I don't know yet about the fuel economy, the boat is far heavier than the designer intended.  Built in too much creature comfort I guess.  I loved the building process except for the painting which I stink at.

 

Egbert

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Egbert,

I am so glad you found a boat for you. So many people are afraid to do what they like, and suffer with unpleasant, cheap alternatives.

There is no any you are going to lose hat beauty in a crowded mooring!

By the by, my solution to the boat lift problem is to stop using it. Just quit doing everything else and spend all your time in that gem you built getting lost in that lovely looking place! :)

Peace,

Robert

Tom, You drew a boat that gets me Right There, you know? Still, if I ever do get a boat with a motor, it will probably have to be, or at least look more like, my beloved Monterrey Boats. Something about that felucca shape just gets me RIGHT THERE. ;)

Peace,

Robert

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Yes, I think new bunks and a forward keel support will greatly add to the security of your boat.  Most likely it may be placed a bit further aft on the lift too if that balances the load better.  Nothing detracts from the great job you did on building her though.  And yes, it will not be possible to put the fat lady ashore as her song has already been sung. 

 

This is my mantra to builders that adding a bit of weight here and some more there beyond the design specs will result in having a fat lady aboard and perhaps her accompanist who cannot be put ashore.  Weight is a big factor in ultimate performance in a planing boat.  Bluejackets have a large foot print and can handle greater added weight than most similar boats and your bottom loading is not as high as production boats.  I expect future performance will confirm this.

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Egbert,  I should have added that the current bunks might be kept and another set added to make the total support more spread out both in length and breadth.  Mi ght be cheaper too.  I often use multiple bunks on my trailers because it is often easier to provide more support where it is needed than with just two. 

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Angling and shaping the bunks can be helpful as well, though this doesn't address the forward roller need, it can insure good contact along the bunks.

 

Thanks for you input Paul.  Yes indeed, angling the bunks is often helpful with the forward warped plane although these bunks, as they are, don't go very far forward.  I'm sure Egbert understands the need for keel support forward.  That should take care of the support issue.  We sometimes don't so much solve a problem as trample it to death but it does work.  The trampling of problems is much more seen on other forums with multitudes of replies of varying expertise. 

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Egbert,

I am so glad you found a boat for you. So many people are afraid to do what they like, and suffer with unpleasant, cheap alternatives.

There is no any you are going to lose hat beauty in a crowded mooring!

By the by, my solution to the boat lift problem is to stop using it. Just quit doing everything else and spend all your time in that gem you built getting lost in that lovely looking place! :)

Peace,

Robert

Tom, You drew a boat that gets me Right There, you know? Still, if I ever do get a boat with a motor, it will probably have to be, or at least look more like, my beloved Monterrey Boats. Something about that felucca shape just gets me RIGHT THERE. ;)

Peace,

Robert

 

Tiger,  I wanted to say that I did look at building an SOF canoe but after calculating the projected weight, I found that it would weigh significantly more than my B&B Birder kayaks so I abandoned the idea.  Could not really cotton to the lighter Monfort design although they are very elegant.  I thought the Monfort skin too fragile compared to the tough but much heavier material Kudzu recommends.

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I did a few measurements, the bunks are 14 feet long.  The way it sits in the pictures the transom overhangs by 20" and the bow about 10 feet.

Lengthening the bunks to 20 feet and creating some support for the keel at the forward end should be the way to go.

 

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Egbert,

Please excuse my drift. After this, I will push the leeboard fully down...

Tom,

The first boat I built by myself was a West Greenland style kayak, anthropometrically measured and all. Rack 'o eye, as it were. I had previously helped a friend build a cedar canoe. Yes, Virginia, the canvas kind. We built a boat, then built a boat on top of it! :)

Anywho, I am a designer, artist, and builder, so the tied together boat just tickled some button, you know.

From ther I devolved to wood/strip, regular old wood (carvel and lapstrake dinghies and canoes/pirogues), and plywood. I only found Kudzu Jeff's boats recently, but they are really neat. I quick, simple way to build a boat, and if you do it right, there is no sanding!

Whoo-hoo!

For the record, those Monfort boats are a little scary light to me, too. :)

Thank you for your time and interest.

Peace,

Robert

Back to you, Egbert.

Thanks for more shots of the boat!

Have fun, brother.

Peace,

Robet

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Egbert,

 

Those bunks look better than I originally thought as they are wide and the angle appears to be adjustable.  I am not sure that a 20' bunk would conform to the hull (or maybe they can) but longer than 14' is surely needed.  Are these bunks able to twist under load or with adjustment?  In any event, more support of the 10' overhang is needed to be certain of not causing any issue forward.  I do remember that you did add quite a bit of weight forward and I suspect that the CG of Pur Dee is further forward than other BJ25's.  It's a relatively simple problem and I'm sure you will handle it well.

 

Edited;  Just took a longer look at these bunks.  The seem to be locked at an angle that is too high and are supporting the aft bottom only on the outer edge.  If so, that is not good.  They appear to be set for a deep V hull. 

 

Robert,

 

I've followed some of your boatbuilding activities and find that I also do a broad spread of different projects, boats, furniture, brick a brac, knives and other twaddle. 

 

Tom

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The 20 feet bunks will not support the hull forward, 16 feet is about the max from the transom to where the hull goes off the bunks forward.  The extra length will give me something to attach a cross brace to support the keel further forward.

I'll check the angle of the bunks.

 

Egbert

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I know a picture is supposed to be worth a thousand words but every time I look at those bunks, they look different to me.  Now I see that I was misled by the apparent down bevel cut on the forward end and tough that the bunks were wide metal and not think they look tall, narrow and wood.  If that is true, disregard almost all I said earlier today. 

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