BBIII Re-build

David Palmer

David Palmer

Active member
Hey folks! I came across this BBIII this winter and will be refurbishing it this summer. I have two questions about my boat's spontoons:
[*]The cockpit combing does not extend to the spontoons. Should I extend the combing or are there other ways to add support to the spontoons? [*]Also, I believe the spontoons have some water in them. Should I drill a hole in the bottom of the spontoons to allow for drainage, or should I remove the half inch plywood on the deck to see what damage the water might have caused?[/LIST]
Thanks!

David
View attachment IMG_3602.jpgView attachment IMG_3603.jpgView attachment IMG_3604.jpgView attachment IMG_3605.jpg
 
David Palmer said:
Hey folks! I came across this BBIII this winter and will be refurbishing it this summer. I have two questions about my boat's spontoons:
[*]The cockpit combing does not extend to the spontoons. Should I extend the combing or are there other ways to add support to the spontoons? [*]Also, I believe the spontoons have some water in them. Should I drill a hole in the bottom of the spontoons to allow for drainage, or should I remove the half inch plywood on the deck to see what damage the water might have caused?[/LIST]
Thanks!

David
Click to expand...

Hello David,

In regards to question #1 ; I'll dig out my plans but off the top of my head I don't feel the cockpit combing would be considered a structural member in regards to sponsoon support. Does it add some support? Yes but I don't think it is significant.

As to question #2; If you suspect water intrusion I'd just go ahead and open up the top decking. You will need this open to do a repair, if one is needed. Rather than go crazy and tear off all the decking over the sponsoon, you might open a spot which could be closed back up with a 8 inch round hatch.

There are numerous threads in the archives will give you an understanding of this hull. There may be additional work you decide to do after viewing these threads. A recent thread; www.duckboats.net/cgi-bin/forum/gforum.cgi?post=331601;do=post_view;forum_view=forum_view_collapsed;page=unread#unread

Do you have a set of the build prints for this hull?
 
The sponsons don't rely on the coaming for strength. It's cosmetic. I'd extend them for aesthetics sake, or alternatively box in the rear of the cockpit and butt the new boards against them.

The water soaked foam has got to go. I would cut round openings in the front of the sponsons and dig it all out. Then install circular screw-in hatches after filling the open space with closed cell foam. If you ever need to get back in there just unscrew the hatches and pull out the foam. Pool noodles could be cut and packed in.

Eric
 
HI Dave.
That's not the boat Eric had posted for sale, is it? Looks like a real project.

That looks like a hole going into the floatation compartment of the sponson. I would want to open them up and see what is going on, particularly with the hull. You might find a bunch of waterlogged foam sitting directly on the hull that needs removed. Not too long ago someone posted a rebuild from a similarly constructed boat (seem to recall a Devlin Mallard) where they found a real mess. Might be worth searching for that post.

Don' t think the sponson itself should need reinforced from the combing, but from a structural perspective would want the combing to at least overlap the rear bulkhead to better tie in the deck(which from the picture, it looks like it is 3/4" short).

v/r
Bill
 
Dave, when I replaced the coaming on my Scaup this past Fall, I did not extend either. I know Eric did on his build, and I thought long about it, but was not ready to open them to gain access. I don't believe sponsons need any support, the coaming would not offer much if any.

If you have water in the sponsons, you definitely need to get it out, and inspect for real damage. I intend to open mine to install a rear dog platform, and am debating on the inspection ports as Steve and others have installed, or a deck level rectangular port.

Dave McCann added coaming across the back at the motor, and the splashwell inserts. I have not experienced the same water coming in while backing down on decoys in the Scaup, so not sure I will add that on mine yet. I will trim the corners to ensure I don't damage them with the outboard, so maybe that creates the bottom drains initially on your sponsons?

Do you have foam?
 
The post I am thinking of was a Bluebill. Not for the faint of heart.


http://www.duckboats.net/cgi-bin/forum/gforum.cgi?post=308120;do=post_view;search_string=soaked%20foam#p308120
 
Thanks for all of your responses. My biggest concern was the crack where the combing ends and the spontoons begin. I don't believe the crack extends very far, but it still raised some concern in me.

Thanks again everybody!

David
.View attachment IMG_3603.jpg
 
David~


I've installed numerous Beckson deck plates - usually to provide access to flotation chambers in a variety of vessels.


https://www.jamestowndistributors.com/userportal/product.do?part=4716&engine=adwords&gclid=CjwKCAjw-YT1BRAFEiwAd2WRtu7XAgvU9rMEhyD1LOhBn84heKfl1i9B0RYQ4c4vJ_Pjo-KCp2w4ThoC5poQAvD_BwE


Although I've never worked on a Black Brant, I would be tempted to install them in the forward bulkhead of each sponson - and avoid the deck itself.


I like Eric's idea of filling with removable foam pieces instead of pouring in new closed-cell foam. Pool noodles would certainly work - but you might also slice up some closed-cell insulation board for this purpose.


Best of luck with your rehab!


SJS





 
Yeah my bluebill was toast but the seller didn't know and at the price I bought it the risk was low. However I am now gun shy of plywood boats. Basically if I build one now I will fiberglass the interior. The boat was also build from Fir ply probably exterior grade and once the rot got into the plywood it spread down the interior and began rotting the Ply from the inside out.
 
Thanks for the feedback, Huntingdave. I don't have the plans for a BBIII and wondered if the spontoons had any strongbackst. The plywood decking on the spontoons don't feel like they do. Didn't know if I should feel worried if I stood on them.

Grace and peace,

David
 
David Palmer said:
Thanks for the feedback, Huntingdave. I don't have the plans for a BBIII and wondered if the spontoons had any strongbackst. The plywood decking on the spontoons don't feel like they do. Didn't know if I should feel worried if I stood on them.

Grace and peace,

David
Click to expand...


Have you read Devlin's book? Understanding the build process would be key to a quality repair.
 
David Palmer said:
Thanks for the feedback, Huntingdave. I don't have the plans for a BBIII and wondered if the spontoons had any strongbackst. The plywood decking on the spontoons don't feel like they do. Didn't know if I should feel worried if I stood on them.

Grace and peace,

David
Click to expand...

David,
Just a bit of background info for you. I have a set of plans, my intent was to build, however the hull I have came up for sale at just the right time and I purchased it completed. The hull as purchased was built "according to plan". I have made several modifications to the hull. Some of those are quite common across the board, trimming the motor well lower corners=common, adding trim wedges under the trailing edge=semi common, adding a splash guard in the motor well= semi common, extending the combing around the rear of the cockpit and into the motor area= my own personal preference.

That said and getting back to your hull. I consulted the plans. The decking should be one continuous piece from about mid-ship to the stern. Therefore you have cause to be concerned about the cracking shown in your photo. The decking over the sponsoons is supported in two ways; (A) the sidewalls provide support around the perimeter (B) the compartment filled with foam and trimmed flush with the perimeter, provides additional support across the field of the decking. How much additional support and if that additional support is needed, is debatable.

Either way, filled or unfilled, I do not believe you should be experiencing any flexing. I also believe the presence of the crack indicates that flexing is occurring. The other possibility is that the boat was not built to plan and there may be a butt joint at that point. Regardless of the cause, the best solution will be to address the cause and fix that rather than a cosmetic fix of the surface.

My advice would be to grind away a shallow dish along the crack. (you will need to do this just to repair the fiberglass layer) Once the glass layer has been removed you will be able to access the condition of the substrate. The conditions you find will dictate the direction of the repair required. (is it an open butt joint , is the plywood separating, etc.)

As far as suspected moisture trapped within; Consider if you wish or need to trim the corners of the motor well. If so, this will both give you a temporary "drain" and a window into the condition of the wood at that point.
Otherwise gaining access thru the forward face of the compartment is a popular option. Personally I'm at that point in life where I'm not as flexible as I'd like. Therefore I'd cutout a panel in the top surface giving me the best access for addressing the concerns presented. Yes there will be additional work to close in the decking and yes I may even add a hatch in the forward face as previously mentioned. I'd still hack open the decking if I felt like I needed to get in there to fix whatever needed fixed, but that's just me.

Good luck moving forward and we are all willing to give you our best advice, leaving you to sort it out. [;)]
 
Good morning, HD - and David, too ~


I was drawn to your thoughts about the ever-diminishing bodily flexibility - not of the vessel but of the builder/owner.


With 2 artificial knees and 67,000,000 miles on my personal odometer, I try to get comfortable when attacking any problem. So, for a job like this one, I would probably flip the boat over (via chain hoists) and set it on my tallest (~ 48 inches) horses. I then work from the comfort of a shop chair - and make sure I put plenty of light on the subject.


View attachment 8 Inverse work station.jpg



All the best,


SJS






 
Steve Sanford said:
Good morning, HD - and David, too ~

I was drawn to your thoughts about the ever-diminishing bodily flexibility - not of the vessel but of the builder/owner.

With 2 artificial knees and 67,000,000 miles on my personal odometer, I try to get comfortable when attacking any problem. So, for a job like this one, I would probably flip the boat over (via chain hoists) and set it on my tallest (~ 48 inches) horses. I then work from the comfort of a shop chair - and make sure I put plenty of light on the subject.

All the best,

SJS
Click to expand...

Steve,
You will have to swap that 67 for a 69 this year for me. Still running on all original parts but some days I question how.
I have flipped a hull as you describe and yes, that is sometimes the best angle of attack. I flipped my hull when I trimmed the corners and added the wedges.

At my former place of employment we have built (for our customers) very large rotating fixtures used during their welding process. One example would be a fixture holding a frame for a combine head or a tractor frame or a motorhome chassis. All the individual pieces would be clamped in place and the welding of those pieces begun. The entire fixture was balanced and supported on bearings at both ends. Being balanced, the welder could rotate and lock the rotation at intervals, giving him the best access and avoiding running vertical or overhead welding beads.
 
Steve Sanford said:
Good morning, HD - and David, too ~


I was drawn to your thoughts about the ever-diminishing bodily flexibility - not of the vessel but of the builder/owner.


With 2 artificial knees and 67,000,000 miles on my personal odometer, I try to get comfortable when attacking any problem. So, for a job like this one, I would probably flip the boat over (via chain hoists) and set it on my tallest (~ 48 inches) horses. I then work from the comfort of a shop chair - and make sure I put plenty of light on the subject.






All the best,


SJS

Click to expand...


I was thinking the same about working from underneath. My 2 cents from uncomfortable experience is to add a fan for ventilation, especially if there's oil based paint/solvent around. Blows the dust out too.
 
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