c.1965 13-footer Hull Drains

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f1loco
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c.1965 13-footer Hull Drains

Postby f1loco » Wed Jan 12, 2022 1:51 pm

I plan to take my c.1965 13-footer with a Yamaha 25-HP engine with tiller-steering to the [Florida] Keys in the summer of 2022. I am concerned about rain at night--common there--while the boat is on a mooring. My 13-footer has no battery, so an electric automatic sump pump is not an option.

[Implied question:]
Q1: will a c.1965 13-footer sink if the cockpit sump overboard drain is removed and there is rain?

Q2: on a c.1965 13-footer which drain holes should be plugged?

Q3: what is the purpose of the original "dual" transom design seen at the stern of a c.1965 13-footer?

jimh
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Re: c.1965 13-footer Hull Drains

Postby jimh » Thu Jan 13, 2022 7:38 am

f1loco wrote:Q1: will a c.1965 13-footer sink if the cockpit sump overboard drain is removed and there is rain?
The Boston Whaler boats are called the Unsinkable Legends. They do not sink.

f1loco wrote:Q2: on a c.1965 13-footer which drain holes should be plugged?
Advice about through-hull drains is given in the Owner's Manual. If you do not have a printed copy of the Owner's Manual, you can read my HTML version in the REFERENCE section of the WHALER section of the website at

https://continuouswave.com/whaler/reference/manual9-17/

The topic of hull drains is discussed under the heading DRAIN TUBES. See

https://continuouswave.com/whaler/refer ... drainTubes

To prevent build up of water while the boat is left unattended on a mooring, all drain plugs are removed.

f1loco wrote:Q3: what is the purpose of the original "dual" transom design seen at the stern of a c.1965 13-footer?
The term "dual" transom is unknown to me. I infer you are asking about the tall and full-width engine splash well at the transom as illustrated below in Figure 1.

Image
Fig. 1. The full-width engine splash well on a classic c.1965 13-footer. Photo by the author.

The full-width splash well bulkhead:
  • adds strength to the stern of the boat
  • creates the engine splash well which is designed to keep any water splashing over the transom from getting into the cockpit, and
  • also provides the stern cleats in the form of two Norman pins passing through the bulkhead.

f1loco
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Re: c.1965 13-footer Hull Drains

Postby f1loco » Fri Jan 14, 2022 2:52 pm

Thanks for the [information0.

I had a bit of stress of my head about leaving [the 1965 13-foot hull] in the water with no plug in the [drains]. I hope the foam age age greater than 50-years-old iss sufficiently "buoyant" to still keep [the boat] relatively dry.

Also, I greatly appreciate the link to the manual. Will keep it book marked for future reference.

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Phil T
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Re: c.1965 13-footer Hull Drains

Postby Phil T » Fri Jan 14, 2022 3:02 pm

Just to be clear, there should be a brass drain tube in every through hull drain. The water tight connection is made by the end of the tube being flared back compressing an O ring against the hull.

If even one drain does not have the brass drain and an 0-ring in good shape the boat should NOT be in the water.
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f1loco
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Re: c.1965 13-footer Hull Drains

Postby f1loco » Fri Jan 14, 2022 3:06 pm

Correct, had fun replacing all four with new o-rings a couple of years ago .. not to mention a bit of transom/glass work from the previous owner.

jimh
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Re: c.1965 13-footer Hull Drains

Postby jimh » Fri Jan 14, 2022 6:05 pm

The buoyancy of any hull is determined by the hull form. The buoyant force has nothing to do with anything inside the hull. As a hull becomes deeper in the water, it displaces more water, so the buoyant force increases. As long as the buoyant force is greater than the weight of the hull and its contents, the hull will float.

The construction of a Boston Whaler boat employes a double bottom hull. The space between the outer hull and the inner liner is completely filled with foam and is sealed. In this way, no water can enter this space, which on a normal boat would be called the bilge space and would be completely open.

Because no water can enter the space between the inner liner and the outer hull, the only water that can come aboard a Boston Whaler boat is water contained in the cockpit. All Boston Whaler boats have greater buoyancy than the hull weight plus the weight of the cockpit filled with water. The result is the hull remains afloat.

Federal regulations require all boats to maintain "positive floatation", but the Boston Whaler boat typically has a much greater reserve buoyancy. Boston Whaler lists the reserve buoyancy of their hulls as the "Swamped Capacity." The Swamped Capacity is the amount of additional weight added to the hull when the hull is completely swamped with water that can be maintained afloat.

For a typical 13-foot hull the Swamped Capacity is 1,600-lbs. This means that even with the hull filled with water--swamped--the hull will remain afloat with up to 1,600-lbs of additional weight aboard. (Of course, that figure refers to a new hull whose dry weight is at the original specified weight.) Some hulls, such as 25-foot OUTRAGE hull, have an enormous Swamped Capacity of 9,000 to 10,000-lbs. This occurs because a very large volume of the hull is filled with foam, an that large volume cannot be filled with water.