Wave Over The Stern (Pooped)

[Sea Skipper]

Lately I find my self remembering some of the high wind against current short period steep waves I was in earlier this summer and thinking about methods to raise the splash well on my CD25 "Sea Skipper". Several owners have successfully done this on their CD22s, but it is not so easy a task on the 25 due to the transom seats. Before I get carried away with worry and perhaps design some useless addition which only gets in the way; I thought I should ask if any C-Dory owner has actually experienced a wave over the stern and lived to tell about it. A CD25 was lost in Cook Inlet, Alaska last year due to being effectively anchored stern to the waves (posts indicated that the rode fouled around outboard lower unit while weighing anchor). To my knowledge, I have never come close to being pooped, but I have only taken brief glances astern when it is that rough out. Thanks -

[Dora~Jean]

Hank,

Interesting subject. I have the '03 model which is completely open under the splashwell from the cockpit, I'm not sure if they enclosed that area in '04, '05 or '06? Mine has 4 large openings between the cockpit and the bilge area back against the transom, approx 12-15 sq in. each. They are used to pass cables and hoses from the cockpit area to below. I'm more concerned about those openings than the splashwell height, I'm planning how to seal them.

[Captains Cat]

Hank, I would think because of the wide flat bottom that it would rise quickly with a sea under it and there would be little chance of taking a wave over the stern unless it were breaking. It's not impossible I suppose but I think highly unlikely. Never had an instance that has been reported here that I know of.

Charlie

[lloyds]

We only have a 16' but the design is similar. We gave it a try in Blackfish Sound last summer, near telegraph cove. Short, steep waves, about 6 to 7 feet, howling wind. Pointed into the wind, took it out of gear. The boat immediatle came around stern to the wind and waves, then just lifted up at the stern and the waves passed under. Sometimes it lifted pretty steep and you had to hold on, but none came into the splashwell, and the boat never broached. Glad I tried it, now I feel much better.

[1TUBERIDER]

Hi Sea Skipper

Taking a wave over the stern is rare and I think Charlie's response is accurate. However

If your attached to the bottom from your stern, swell could come over,
if your hanging off the transom clearing an engine, water can splash in,
or if you are backing down, water can splash in.

A local sheriff tied off on a sunk drift boat and tried to tow it down stream, as soon as the line tighten the boat swamped. Water came over the stern. Everyone was ok. If he would have pulled it up stream he would have had better control and would not have taken on water.

Normal operations should sea very little water come in. A splash could come thru your scuppers, but will usually drain out.

I would not modify your boat. Boat safe.

1tuberider

[Levity]

I tied my boat to a dock with the bow facing the prevailing wind and left it overnight. During the night the wind shifted 180 degrees and picked up to 20 kts. The stern was now exposed to a 5 mile fetch. By the time I returned to the boat water was splashing over the transom and being blown as spray and driven in small streamlets into the cockpit. There were 4 inches or so accumulated in the depression where the transom bilge pump is located. This pump does not have a float switch and is manual on/off via a switch in the cabin. I observed that the stern line was taunt which prevented the stern from rising high enough to ride completely over the waves. In fact, the stern was being abruptly halted in it's natural response to the wave energy. When the stern line was loosened the stern was free to rise to the waves and the streamlets ceased to enter the boat but the spray continued although significantly lessened. The longer stern line allowed the boat to buck and yaw energetically while making contact with the dock so I turned the boat around.
A built up splash well may not be necessary to keep water out of the boat when it is free to respond naturally but may help when the boat is hindered in its response to wind and wave.
Mike 'Levity'

[Dora~Jean]

The CD25 is self-bailing and the cockpit to bilge area is sealed. The ports and hatches installed in the cockpit floor leak a little, but if all hatches are closed, even filling the cockpit with water in my opinion will not cause more water to enter the bilge area than the pump will be able to keep up with (unless it's broken or disabled).

Still, my only concern on my boat are those 4 open pass-thru's that could allow volumes of water in which the bilge pump will definitely not keep up with. I'll post my mods once I settle on a method...!

[james]

Mike, you are one brave man OR you have a really good insurance policy.

got to get a float switch.

also in regards to bilge pumps, everything I read points to most pumps being woefully inadequate.

I have the 2200 on my 22 ft.

http://www.johnson-pump.com/JPMarine/products/bilge/l-series.html

also a rule 1100 in the cut out under the stove.

James

[thataway]

The vast majority of boats which sink with waves over the stern are restrained by either an anchor, fouled line, or dock lines. The stern of the semi dory hull rises so rapidly--that I think, even a breaking wave--(If the operator remains control, and prevents a broach) would not poop and fill the cockpt. I do agree that if you have any openings, to the bilge that they must be sealed in some way. The TC 255 has affected this with the access hatches. If I had a CD 25 I would certainly make this modification and put in a much larger bilge pump, with float switches on both pumps. Of course once a cockput is full of water--the boat's handling characteristics change rapidly--and the cockpit drains are totally inadequate to handle the volume of water out. Increasing the size of the spash well would probably not change this equation much.

Remember that pumps are rated with zero head--these open vane pumps loose volume very quickly as output head is increased.

I have been in 40 foot breaking seas in a larger boat--and the boat always lifted enough to allow the majority of the wave to safely pass under the boat--the boat had way on--and thus was not restrained by a drogue or sea anchor--which actually might make the situation more dangerous.

[james]

[thataway]

One has to differentate between a Sea Anchor and a series drogue. The Series Drogue (called Jordon Drogues) are on a long line, with multiple cones to slow the foreward motion of a boat down, and keep the stern to the breaking waves. One wants to prevent being beam to the large seas.
A Sea Anchor is deployed off the bow, and allows backward drift. In a C Dory this would make some sense--wereas a drogue or sea anchor off the stern would be dangerous. One has to size the sea anchor for the type of boat. A good sea anchor is strong, has a trip line, sinkers on the bottom and a float on the top. There has to be a strong point to anchor it foreward and adequate chafing gear.

[Sawdust]

The only time I have a lot of water over the transom with the 22 is when shrimping. The heavy shrimp pot is like a sea anchor and the boat points down sea with the stern taking the brunt of the weather. Boots on, both bildge pumps on, and hope some newbie with a stern wave higher than the radar doesn't come by. (New Year's resolution - no brand name of boat mentioned )

When off Swiftsure digging for halibut, back-trolling to try and get your hali rigs to the bottom in 500+ ft. of water, water over the transom is just the way it is. Pumps and boots.

I'd like to find a good (easy) way of keeping the water out, but I'm still planning to shrimp and hunt halibut.

Dusty

[Chris Bulovsky]

Wile fishing on Superior in a place called the Flats last summer I had swells from the North east and a gusty wind from the south that made some cone like waves. Kinda ugly .

I took several of these into the "slash well" while trolling and the self scuppering transom did what it was supposed to do. That day reinforced my opinion that I have a big water boat. I have yet to use my bilge pump for anything other than rain water.

Its a remarkably dry cockpit, pending that you don't do something stupid in big water. I think this is true for most boats.

I would hold off on the modification until you see a definite need. The design is sound on the 25'. (pretty smart advice from a guy who doesn't have a 25' ...............yet )

Chris Bulovsky
Washburn Wi

[Sea Skipper]

Well - despite all the good advice to the contrary, I decided to raise the splash well.



The forward portion of the splash well was raised 10" and is now even with the gunnel effectively increasing the aft free board from 18" to 28". The splash well filler is made from 0.090 (3/32") aluminum sheet bent on a hydraulic press with the top edge measuring 1-1/2". only the mitered corners of the top edge required welding. The assembly was fitted to the boat then powder coated to match hull color. The powder coater used a primer and 5,000 hour rated saltwater resistant paint. I bent the handrail from 7/8" stainless steel tubing and drilled holes in the top edge to match with sockets machined from aluminum below. The whole assembly with railing weighs about 16#. The railing is very sturdy and lifts out for additional access if desired. Total cost was about $375 which does not include the railing or installation. The existing camper back snaps were utilized for mounting so no canvas recuting was required.

Benefits:
More free board and less likely to take a wave over the stern
Aft railing for safety
Less engine noise as some of the sound should be deflected (this last to be determined)

Disadvantages: The cockpit will now hold 2 tons of water rather than 1 ton; but, in storm conditions, it probably wouldn't make much difference in the final outcome.

More pictures in the Sea Skipper album.

[oldgrowth]

Sea Skipper – it looks good. I like the idea of a higher splash well.

Why the second kicker on the port side of the boat?.
________
Dave