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Tom Lathrop

Recent Bluejacket news

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In case some people have wondered what is going on with Bluejackets, this is the latest.  Plan sales and building is moving along, although at 88, I have started slowing down on all facets of boating.

There have been several inquiries about whether a Bluejacket can be built in Aluminum.  My answer has always been that a BJ can certainly be built in aluminum but I am not in a position to do detail design and manufacturing in that medium.  Quite a few aluminum boats have and are being built in the Pacific Northwest and are used mostly for fishing.  None of these boats are, to my knowledge, optimum for cruising, which is a Bluejackets stock in trade.  Weight of aluminum is a lot greater per unit of volume than wood which is the main reason that attempts to use other materials have not been pursued to a good conclusion.  Weight of the boat and resultant performance advantages of light weight was the driving force behind many decisions in the Bluejacket design.

Earlier this year, a builder of aluminum boats in Melbourne, South Australia contacted me about the possibility of using aluminum for 100% of the boat structure.  After considerable discussion of what would be involved and by his enthusiasm for the project, work was started on evaluating whether a Bluejacket could gain the benefits of non-perishable material and rugged aluminum structure while retaining its better qualities of performance of the wooden model.  Of course, the benefit of an ability to buy a commercially built Bluejacket from a quantity builder was also a main factor.  How well this is accomplished is a bit unclear but the prospects look good.

While I did do some work on this project, the main effort has been from John Pontiflex who owns and operates Plate Alloy Australia Pty Ltd in Melbourne, Victoria, Australia.   He builds a fairly large range of aluminum boats that are used mainly for fishing, either commercially or privately.  Some modification of structural parts of the wooden Bluejacket was required to utilize aluminum but the design was followed very closely.  He says that cruising boats are not a big item in Australia at this point and none that approximate a Bluejacket are available.  Therefore a commercially available aluminum Bluejacket may well be a viable offering for Plate Alloy.  He also teaches aluminum boatbuilding and the welding techniques necessary to make a good job in one week (or so) courses in various areas of Australia.  CNC kits can then be a large part of Plate Alloy’s offerings.  Cut files are, of course, available but legal requirements safeguarding their use by those other than Plate Alloy will be required.

Shipping costs of ether boats or building material from Australia to the USA are high.  Such costs may make shipping of boats or part inventories infeasible but that can be worked around is not known yet.

The attached photos show the boat in its unfinished form at the trial launch.  The engine is not equipped with final controls and is a larger size with much more weight than the 70hp specified.  This engine is a larger than recommended size as that is what John had at the time.  Performance is expected to be good with the recommended engines up to the Yamaha 70hp model.  Yamaha outboards from 50hp to 70hp all have the same displacement although the 70hp will provide the best high end speed.

 

In case some people have wondered what is going on with Bluejackets, this is the latest.  Plan sales and building is moving along, although at 88, I have started slowing down on all facets of boating.

There have been several inquiries about whether a Bluejacket can be built in Aluminum.  My answer has always been that a BJ can certainly be built in aluminum but I am not in a position to do detail design and manufacturing in that medium.  Quite a few aluminum boats have and are being built in the Pacific Northwest and are used mostly for fishing.  None of these boats are, to my knowledge, optimum for cruising, which is a Bluejackets stock in trade.  Weight of aluminum is a lot greater per unit of volume than wood which is the main reason that attempts to use other materials have not been pursued to a good conclusion.  Weight of the boat and resultant performance advantages of light weight was the driving force behind many decisions in the Bluejacket design.

Earlier this year, a builder of aluminum boats in Melbourne, South Australia contacted me about the possibility of using aluminum for 100% of the boat structure.  After considerable discussion of what would be involved and by his enthusiasm for the project, work was started on evaluating whether a Bluejacket could gain the benefits of non-perishable material and rugged aluminum structure while retaining its better qualities of performance of the wooden model.  Of course, the benefit of an ability to buy a commercially built Bluejacket from a quantity builder was also a main factor.  How well this is accomplished is a bit unclear but the prospects look good.

While I did do some work on this project, the main effort has been from John Pontiflex who owns and operates Plate Alloy Australia Pty Ltd in Melbourne, Victoria, Australia.   He builds a fairly large range of aluminum boats that are used mainly for fishing, either commercially or privately.  Some modification of structural parts of the wooden Bluejacket was required to utilize aluminum but the design was followed very closely.  He says that cruising boats are not a big item in Australia at this point and none that approximate a Bluejacket are available.  Therefore a commercially available aluminum Bluejacket may well be a viable offering for Plate Alloy.  He also teaches aluminum boatbuilding and the welding techniques necessary to make a good job in one week (or so) courses in various areas of Australia.  CNC kits can then be a large part of Plate Alloy’s offerings.  Cut files are, of course, available but legal requirements safeguarding their use by those other than Plate Alloy will be required.

Shipping costs of ether boats or building material from Australia to the USA are high.  Such costs may make shipping of boats or part inventories infeasible but that can be worked around is not known yet.

 

The attached photos show the boat in its unfinished form at the trial launch.  The engine is not equipped with final controls and is a larger size with much more weight than the 70hp specified.  This engine is a larger than recommended size as that is what John had at the time.  Performance is expected to be good with the recommended engines up to the Yamaha 70hp model.  Yamaha outboards from 50hp to 70hp all have the same displacement although the 70hp will provide the best high end speed.  The video does not work for me as yet.

 

BJ 25.5 showingcockpit hatch.JPG

first trial launch of BJ25.5.JPG

mini-IMG_5475.JPG

Edited by Tom Lathrop
correction
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Looks like an interesting project.  Do you know the specs on this one like the weight and the length?

Also noted the cockpit door and a railing. 

 

Egbert

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I know some facts Egbert, but am waiting to get more definitive data after the boat has completed construction and trials.  Each model will be somewhat heavier but I don't think it will be as great a change as I originally feared.  This is due to my assessment of the knowledge and skill of Plate Alloy in use of aluminum in building boats.  Some features of the Bluejacket design are effective in mitigating increase weight.  Probably foremost of these is the large water plane and buoyancy that offer a much lower bottom loading in weight per square area compared to other boats.   At least in these boats, less weight means more performance while using less power and fuel than commercially available options.

 

For those who have a desire to build or have a wooden boat, I don't think the aluminum version will be a great deterrent to building the current wooden model.  For those with less time, space  or opportunity to build their own, as well as finances to buy a more expensive aluminum one, availability of a commercial Bluejacket will be a positive.  For my part, I still favor the current wooded model because I just like the ability to build my own. 

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Egbert, now that you have your boat loaded to the hilt and your boat has some hours on it now in a wide variety of conditions, can you post your performance numbers, fuel burn, speeds and the likes? Thxs

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Never really tracked the fuel consumption accurate.  In general I get according to the gps around 3.3 mpg at speeds above  6-7 mph..

It doesn't seem to make much difference what speed I'm going.   The top is about 21 mph.   Weight full of liquids must be close to 4400 lbs.

Engine is a 75 hp Evinrude.  Propeller 14 x 13.  That should be a 14 x 11, the 13 doesn't get to the rated rpm for that engine.

The big problem I have with that engine is the vibration at idle speeds.  Going anywhere at no wake speeds is horrible. Going at a speed where the vibration stops results in people yelling an gesturing at me.

I am changing the 2 stroke oil to the xd100 which will be equivalent to 100 to 1 mix.  Also need to take it to a different dealer for service.  Previous one blamed it on my gas.  They replaced filters and the result was no improvement.  The engine shakes at idle speed even without the gear engaged.

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I have a 90 etec on a 22 Simmons with the same vibration issue at idle. Of course its one of the same linage of your engine. Its my understanding that they have updated the engines and they are better.  Thxs

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I posted this thread with the thought that wooden boat builders would have some thoughts about aluminum as a viable and practical material for a Bluejacket.  So far, none have expressed any thoughts along those lines, such as:

 

What are opinions of aluminum versus plywood as a boat material?  That is, not regarding the obvious ones of building expertise or price.

What are the issues in contemplating an aluminum boat for the average home builder?

Which is more desirable aesthetically?

Which would you rather own?

Which is less maintenance?

Anything else?

 

 

 

 

 

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What I asked is clear.  No opinions were offered from me.  I did not ask anyone to evaluate the Australian builder I am using although they have many successful aluminum boats as well as provide extensive hands on training for prospective builders.  I understand and stated that boats or kits shipping from Australia may too much for many in the USA. 

 

The questions were only related to what issues wooden boat builders might have with aluminum as a material.

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