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post #21 of 37 Old 07-06-2019
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“And while big boats can tolerate all kinds of small adjustments in loading, small boats are pretty intolerant of extra weight and where it is placed in the boat.“

People bolt on an over grown egg beater to the stern. Not a good place to add weight. I would think a more centralized located inboard, albeit a little heavier would be the way to go. Especially on this full keel boat which probably sails like a bathtub anyway.
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post #22 of 37 Old 07-06-2019
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Re: Can this boat be saved

Quote:
Originally Posted by cousineddy View Post
“And while big boats can tolerate all kinds of small adjustments in loading, small boats are pretty intolerant of extra weight and where it is placed in the boat.“

People bolt on an over grown egg beater to the stern. Not a good place to add weight. I would think a more centralized located inboard, albeit a little heavier would be the way to go. Especially on this full keel boat which probably sails like a bathtub anyway.
You would be correct about this if this boat was actually designed to have an inboard engine. It wasn't. This boat was designed to have a light weight outboard mounted aft with the predominant auxiliary outboards of that era being the 30 lb British Seagull Outboard and the 35 lb Evinrude and 30 lb Mercury 4 hp long shaft 2 strokes. Boats like this one were designed to be sailed with their auxiliary engines only used to get into a slip or motor a short distance back home when the wind died.

So while you may be correct that an inboard engine would make a better auxiliary for the way most folks use their boats these days, that would only be true if were starting from scratch to design a small cruising boat that included an inboard in the design concept from the very beginning rather than altering a boat that was never designed to have one.

Further, what makes this an especially poor candidate for this modification is it's extremely short waterline length and narrow beam. Boats like these have comparatively small carrying capacity relative to their displacement because there is such a small water plane that in turn results in very poor ratio of immersion inches per pound.

To put that in perspective, if we think of a modern boat as having a carrying capacity in the range of 20% to 30% if its overall dry weight design displacement, boats like these tend to have a much smaller percentage in the 15-20% range. If you consider that engine and shaft, etc. add roughly 7-8% of the total design displacement of the boat, you can quickly see why adding this particular inboard diesel to this particular boat makes less than zero sense even if only used as a daysailor.

Supporting that conclusion is the first hand report that this boat does not sail well. While the inboard diesel may only being a contributing factor, it would none the less be a major contributing factor.

Respectfully,
Jeff


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post #23 of 37 Old 07-06-2019
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Re: Can this boat be saved

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Originally Posted by davidpm View Post
He like me is put off by the fact that the boat doesn't sail very well.
The boat was designed to be sailed with an overlapping headsail in most conditions. Day sailing in less than 10k of wind with that Hoyt boomed 90% jib, the boat will for sure be a dog. Personally hate boomed foresails and can't see a need for them, especially on a small boat. Newer high aspect rigs are better with no overlap headsails but still need an overlapping sail for best performance in lighter conditions.

Think Jeff is being a little over dramatic in his caution about the inboard engine. The location low down in the hull and more in the middle of the boat won't effect the boats CG and handling all that much and probably helps if we're talking an outboard perched off the stern with all that weight way way away from the CG of the boat.
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post #24 of 37 Old 07-06-2019
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Re: Can this boat be saved

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Originally Posted by roverhi View Post
Think Jeff is being a little over dramatic in his caution about the inboard engine. The location low down in the hull and more in the middle of the boat won't effect the boats CG and handling all that much and probably helps if we're talking an outboard perched off the stern with all that weight way way away from the CG of the boat.
You may be right but I do not think that you are. The impact of the inboard engine is pretty simple math.
Outboard= 35 lbs x 11 feet (CB to CL weight of engine)= 385 ft lbs of rotation
Inboard= 250 lbs x 4 feet (CB to CL weight of engine)= 1000 ft lbs of rotation

These boats tend to squat at speed anyway, but unless you dump a bunch of weight into the bow, the boat is starting out with a squat that will only get worse. These boats pitch a fair amount more than modern boats and dumping a bunch of weight in the bow will only make the boat pitch worse.

But even if that does not convince you, there is the testimony that this boat sails very poorly which seems pretty convincing to me.

Jeff
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post #25 of 37 Old 07-06-2019
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Re: Can this boat be saved

Quote:
Originally Posted by Jeff_H View Post
You may be right but I do not think that you are. The impact of the inboard engine is pretty simple math.
Outboard= 35 lbs x 11 feet (CB to CL weight of engine)= 385 ft lbs of rotation
Inboard= 250 lbs x 4 feet (CB to CL weight of engine)= 1000 ft lbs of rotation
Shouldn't too much weight aft cause Lee helm? Where would the longitudinal centre of bouyancy be on this boat? Maybe 3 ft aft of centre?

Is it possible the inboard engine is causing the boat to trim down by the head?
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post #26 of 37 Old 07-06-2019
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Re: Can this boat be saved

Alberg's designs typically have their center of buoyancy pretty close to the center point between the point of entry and the aft point. For my calculation I assumed that the CB was roughly a foot after of the center point between PE and the AP. Using that as a point of rotation it's very clear that the boat would go down in the stern rather than the bow

And if the boat rotates stern down the rotation arm between the CLR would move a couple inches forward while the CE would several times that aft increasing weather helm.

Jeff


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post #27 of 37 Old 07-07-2019
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Can this boat be saved

Quote:
Originally Posted by cousineddy View Post
“And while big boats can tolerate all kinds of small adjustments in loading, small boats are pretty intolerant of extra weight and where it is placed in the boat.“

People bolt on an over grown egg beater to the stern. Not a good place to add weight. I would think a more centralized located inboard, albeit a little heavier would be the way to go. Especially on this full keel boat which probably sails like a bathtub anyway.


Jeff posted some more convincing math, and maybe he is right, but in my gut I was thinking the same as cousineddy. In rigging our racing boats, we are taught to concentrate all weight and rigging at the thwart, as close to half way between bow and stern as possible. Make-up “penalty” weight is added equally at bow and stern after failing a one-design weigh-in for the same reason, that’s where it hurts you most.

Assuming designers of turd cruisers like this were actually calculating their loading to this degree 50 years ago is likely giving them more credit than they are due, it is not inconceivable that moving ballast from the stern to the centerline may be an improvement in a boat designed with appearance and comfort taking precedence over performance.

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post #28 of 37 Old 07-07-2019
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Re: Can this boat be saved

Quote:
Originally Posted by DinghyRace View Post
Jeff posted some more convincing math, and maybe he is right, but in my gut I was thinking the same as cousineddy. In rigging our racing boats, we are taught to concentrate all weight and rigging at the thwart, as close to half way between bow and stern as possible. Make-up “penalty” weight is added equally at bow and stern after failing a one-design weigh-in for the same reason, that’s where it hurts you most.

Assuming designers of turd cruisers like this were actually calculating their loading to this degree 50 years ago is likely giving them more credit than they are due, it is not inconceivable that moving ballast from the stern to the centerline may be an improvement in a boat designed with appearance and comfort taking precedence over performance.
A couple quick comments, you are correct that if the engine was actually located at the Center of buoyancy, or at least closer to the Center of Buoyancy it would potentially be less detrimental to pitching than it is in it's current position. In this case the problem is a mix of issues that only partially includes the position of the engine. What makes this a bigger problem than it might seem, is the sheer amount of weight. The combination of the weight and position would essentially be like having a small kid sit aft of the helmsman or the helmsman sitting a few feet too close to the transom in a dinghy. It would be noticeable.

I also want to address the comment that it is unlikely that the weight distribution was calculated when the Electra was designed. Even in the 1960's, when I was studying yacht design, one of the early steps in designing a boat was to prepare a table of weights which listed every known item on the boat including small items like cleats, chocks, stern lights etc., and which included a column recording their distance from a fixed point fore and aft and athwartship.

These weights were then totaled to find the dry weight without ballast. The ballast weight was calculated as the difference between the displacement and the weight without ballast.

Each weight and position was multiplied out and the rotational moment calculated. That was divided by the dry weight to give the designer the center of gravity without ballast. Then the center of gravity for the ballast was calculated adjusted and recalculated so that the center of gravity aligned with the center of buoyancy. That process was done both fore and aft as well as side to side.

When that was completed, additional service weight calculations were performed looking for the worst case with tanks full, crew in the cockpit, crew in the bunks, dishes in the cupboard, can goods in the lockers and so on to make sure that the boat when loaded mostly sat on her lines. There was an assumption was that owners would be aware of trim and adjust where they placed things to have the proper trim.

In wooden boats it was common to have 'trim ballast' which was internal ballast that could be moved to help trim the boat to her lines. In the mid-1960's Phil Rhodes told my Dad that the Vanguard was designed to carry roughly 10% of her ballast in trim ballast and was uncomfortable that the boats were delivered without the trim ballast.

I worked for the yacht designer Charlie Wittholz in the 1980's. Charlie worked with Carl Alberg at the Alden office and knew Alberg pretty well. Charlie was pretty much as old school as you get. Charlie's methods would have been similar to those of Alberg's who he worked with. Charlie always did a table of weights on his projects, even small catboats and canoe yawls. By the time that I worked for Charlie he was using an electronic adding machine to do his table of weights calculations rather than a slide rule and a mechanical adding machine, but he was definitely doing it.

In any event, the added weight of the engine would mean floating roughly 1 1/4" lower in the water and roughly 3 -4 degrees down in the stern (unless weight was added forward to counteract the rotation) and that additional submersion and rotation or counterbalance weight doesn't do anything good for the sailing abilities of a boat.

As I noted above, while the added weight of the engine and its position may not be the sole reason that this boat doesn't sail well, my sense is that it would certainly be a contributing factor which is why I would never have added it and might have removed it if I owned this boat.

Respectfully,
Jeff
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Last edited by Jeff_H; 07-07-2019 at 11:47 AM.
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post #29 of 37 Old 07-08-2019
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Re: Can this boat be saved

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Originally Posted by Jeff_H View Post
A couple quick comments, you are correct that if the engine was actually located at the Center of buoyancy, or at least closer to the Center of Buoyancy it would potentially be less detrimental to pitching than it is in it's current position. In this case the problem is a mix of issues that only partially includes the position of the engine. What makes this a bigger problem than it might seem, is the sheer amount of weight. The combination of the weight and position would essentially be like having a small kid sit aft of the helmsman or the helmsman sitting a few feet too close to the transom in a dinghy. It would be noticeable.

I also want to address the comment that it is unlikely that the weight distribution was calculated when the Electra was designed. Even in the 1960's, when I was studying yacht design, one of the early steps in designing a boat was to prepare a table of weights which listed every known item on the boat including small items like cleats, chocks, stern lights etc., and which included a column recording their distance from a fixed point fore and aft and athwartship.

These weights were then totaled to find the dry weight without ballast. The ballast weight was calculated as the difference between the displacement and the weight without ballast.

Each weight and position was multiplied out and the rotational moment calculated. That was divided by the dry weight to give the designer the center of gravity without ballast. Then the center of gravity for the ballast was calculated adjusted and recalculated so that the center of gravity aligned with the center of buoyancy. That process was done both fore and aft as well as side to side.

When that was completed, additional service weight calculations were performed looking for the worst case with tanks full, crew in the cockpit, crew in the bunks, dishes in the cupboard, can goods in the lockers and so on to make sure that the boat when loaded mostly sat on her lines. There was an assumption was that owners would be aware of trim and adjust where they placed things to have the proper trim.

In wooden boats it was common to have 'trim ballast' which was internal ballast that could be moved to help trim the boat to her lines. In the mid-1960's Phil Rhodes told my Dad that the Vanguard was designed to carry roughly 10% of her ballast in trim ballast and was uncomfortable that the boats were delivered without the trim ballast.

I worked for the yacht designer Charlie Wittholz in the 1980's. Charlie worked with Carl Alberg at the Alden office and knew Alberg pretty well. Charlie was pretty much as old school as you get. Charlie's methods would have been similar to those of Alberg's who he worked with. Charlie always did a table of weights on his projects, even small catboats and canoe yawls. By the time that I worked for Charlie he was using an electronic adding machine to do his table of weights calculations rather than a slide rule and a mechanical adding machine, but he was definitely doing it.

In any event, the added weight of the engine would mean floating roughly 1 1/4" lower in the water and roughly 3 -4 degrees down in the stern (unless weight was added forward to counteract the rotation) and that additional submersion and rotation or counterbalance weight doesn't do anything good for the sailing abilities of a boat.

As I noted above, while the added weight of the engine and its position may not be the sole reason that this boat doesn't sail well, my sense is that it would certainly be a contributing factor which is why I would never have added it and might have removed it if I owned this boat.

Respectfully,
Jeff


Awesome post, Jeff. Thank you for setting us straight, you are very knowledgeable on this subject!
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post #30 of 37 Old 07-10-2019 Thread Starter
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Re: Can this boat be saved

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Originally Posted by Jeff_H View Post

As I noted above, while the added weight of the engine and its position may not be the sole reason that this boat doesn't sail well, my sense is that it would certainly be a contributing factor which is why I would never have added it and might have removed it if I owned this boat.

Respectfully,
Jeff
Add dragging a prop through the water and a diesel tank, square-top main, tiny jib the only remaining question is what else they could have done to make it worse.

I know, dingy davits and a dinghy off the back?

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